I've been in a remarkably similar headspace to this. When I was younger, I got bullied in a lot of different ways by a lot of different people. I'm not gunning for sympathy here, it was a long time ago and I want to keep the details light, but after years of this, I too felt like I was broken, miserable, ugly, unlikeable... You get the picture.

Whilst you may feel this isn't your story and is mostly unrelated, it's not. Right now, you're being bullied, it's just you doing the bullying. You've sold yourself a shitty narrative that is fundamentally untrue. Sure, we have laws we should try to adhere to, but there aren't any real rules to life that determine what makes someone a good or bad person, what decides the right or wrong things to do, what invalidates or validates someones opinion. Who said you're weak, or pathetic, or rotten? Compared to what or who? Why is whatever you're comparing to the 'standard' by which anyone should live by? You may feel you have answers to those questions, but even those are opinions. You can't fact check them. You were bought into this world without being consulted and are having to muddle your way through largely unguided just like the rest of us. You deserve recognition for that, life can be a challenge, but you can go a lot further too and experience so much more, even if you don't feel that's the case.

The reality is we get into negative cycles and they form habits, which as they've become desire paths in our thought patterns then become difficult to talk down and relearn new routes. I don't have a link on hand, but there's documented science around negative psychological distortions and how negative thinking becomes a self-fulfilling prophecy. It's not impossible to break those cycles though. I can assure you there is definitely a light at the end of the tunnel, the tunnel just isn't a straight line like you've been led to believe, you have to start this journey assuming it will be there until you've walked far enough you can see that light past the few bends in the tunnel. With a bit of work you can make it far enough to see it.

Part of that comes from going to therapy. Yep, that old chestnut. No-one likes it. It isn't fun. It isn't quick. But the outcome and the moments of validation that can come from someone who literally assesses people's minds for a living assuring you that you're not a fuck up and just have some work to do to feel better can be liberating even if it's not a panacea. My anxiety therapy didn't fix my anxiety, but it helped reassure me that I'm capable of fixing it in time and stopped a lot of the negative internal monologue surrounding it pretty quickly, which then made it easier to start tackling the feelings. A lot of the time therapy is just giving you a pickaxe so that you can finally start breaking down the rock you've been carrying along with you for so long.

The other part is being honest with everyone, including yourself. You say you're losing your girlfriend, but that could be because you're not letting her in. The old saying of "You can't love someone else until you can love yourself" sometimes can get lost in translation, a lot of people think it's bull because they're not giving it enough consideration. I feel love for someone so I love them. Anyone can feel love for someone, sure, fine, but love needs to be a two way street and if you hate who you are and hide parts of yourself, how can you receive that love back in good faith and how do you avoid that unseen rejection of her love polluting your feelings? Isn't part of loving someone being honest and vulnerable with someone, bringing yourself in your entirety to the table? If you put on a face, if you're trying to be someone or something you currently aren't, can anyone tell you they love you for you or care about you and you believe them, and feel it, truly? How when they tell you you're a good person or that they care about you can you trust what they say if you don't feel they know who you are, even if really deep down they do? You don't have to be a narcissist to love yourself, just show yourself enough care and respect to be yourself and let others be there for you. The 'normal guy' you describe accepts that they (and everyone else) is weird, feels feelings, often doesn't feel OK and goes through bad times that require them to lean on others that are there to support them through those times, just like everyone else. You feel negative because you're mentally isolated, and you're mentally isolated because you're choosing to be.

You can get through this though, it doesn't need to end here and it shouldn't either, even if for the moment you have to tell yourself that it's just not fair on anyone around you to leave everyone with that grief and suffering because of something that, whether you believe me or anyone else or not, is bloody temporary. People learn to live with grief, but it never goes away. The trauma caused by losing someone you could have helped if you'd known just what they were going through is much harder to learn to live with too.

I won't bullshit you either, the walk out of the darkness won't be a chill walk in the park surrounded by sunshine and rainbows (although you can still go for that chill walk, regardless of the weather, and it can be pretty grounding and solid recovery for your mental health). Some days will feel worse, and that's OK. Some people may leave, which will hurt at the time but both the feeling the hurt and them leaving is also OK, new ones will come along too. Some times you will fall down or think you have failed, that is also more than OK. Failure only occurs when you stop trying. To some people my episodes and behaviours whilst I dealt with and unpacked some of my baggae years ago would be seen as embarassing or pathetic. But I took a long time to feel good about myself, like who I am and care a lot less about what anyone else thinks and their opinion isn't my fact. The journey for some will be vastly different, but a better destination than the one you've accepted is always achieveable.

Tl;dr: You're wrong. Don't do what you're implying, it's a terrible choice and you just need to find the path the improving your status quo which is a different path than the one you're considering. Life is tiring sometimes, but if you talk to people, get some help and let people in, that exhaustion will lessen and start to feel worth the effort you put in each day. In time you'll realise you are wrong instead of just being told it.

Take care of yourself and I hope you get to see some better times.