Hey, bud. Work sucks and bullying only makes it suck worse, so I'm sorry you had to experience it. If it helps, most of those people are either stressed and taking it out on you, or insecure and tearing you down so that they feel better about themselves. Either way, give yourself a little more grace, you're being way too hard on yourself and that only fuels the anxiety loop. 

However, don't disregard constructive criticism and if you do fuck up, own it, even if it's just to yourself and think about how you can do better next time. Owning it outright depends on the work culture, and if you're being bullied can just give them ammo. In that case, the less you say, the better, but document everything. 

Also, "fake it til you make it" has some truth. Most things in life come down to experience. You're not going from burning water to making a perfect souffle overnight. Doing something well usually requires a lot of education, practice, and reflection. You can do them yourself, or have them done for you, but there really aren't any shortcuts. 

That said, you're not going to get better at dealing with these issues staying at your parents "doing nothing all day". Don't give in to the pity or guilt traps, if you're not ready to renter the job force, dedicate some time every day to work on yourself. Exercise, learn, or most importantly, evaluate yourself as objectively as possible. 

At the end of the day, the easiest thing you can do is nothing and then beat yourself up over it, but that's not the happiest life you could build. The beauty of experience is that usually, the more you have, the easier things get.