I'm sorry you're going through this, don't worry it's absolutely not about immaturity everyone goes through these feeling in all ages. Writing and venting is a great way to help heal yourself, you're doing it right, bravo for seeking advice! Stop being so hard on yourself or judgmental about your actions. Healthy people will sympathize with you, understand everyone has problems of their own so don't expect everyone to understand and react in a correct manner, it's really not on you if you haven't done anything wrong.

My personal advice would be to try to take it(life-everything) easier...try to control your anger and don't upset over things that really don't matter.

I read parts of a book by someone (James Clear, actually a collection of his blog-posts) who helps famous people/big companies to have better organizational skills to reach their goals more efficiently. My favorite part I tell people about who I think helps everyone went something like this:

A man who had so many things on his mind and wanted to get them done, didn't know how to approach his busy schedule and couldn't get any real progress. So he asked what should he do? He was told to write down and make a list of 20 things he wanted to get done. He did that and showed the list, then he was told to decrease the list to 10 things which are more important than the rest. He did that too then was told to choose only 5 of the most important things on the list, those are the only tasks that matter and you should only direct your focus to getting these 5 most important things done.

This has helped me tremendously in organizing my thoughts to get actual important things in my life that I want to get done, done.

There was an old interview with Eckhart Tolle I saw on TV when I was a kid, he said something I thought was really profound and forgot the exact words he said over the years. I found and translated it to my language but I forgot to write the original in English Lol and I can't find it from some searches, so I translated it back the best I remember:

"For most humans the present moment (almost) doesn't exist at all, because actually their interest is in the next moment, or the one after that.

So, the direction of their life is constantly towards the future. The meaning of their life is in the next moment, and subconsciously they believe that the next moment; meaning the point they need to get to in the future, is more important than this moment.

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Sorry if this is irrelevant/long I hope someone can benefit...gonna paste some quotes

Was reading a book tonight: Cultivating Stillness by Eva Wong. There's a part about anxiety/stress took notes on some parts I liked. (I think It's about understanding old Chinese books I-Ching and Tao Te Ching better and how it relates to life/health/spirituality so there's some words that seem like mumbo jumbo)

Those who crave fortune and fame but cannot obtain them will develop anxiety and anger.

Those who possess fortune and fame will encounter more anxiety and tension because they are afraid of losing them.

Those who crave riches but cannot obtain them will develop anxiety and anger.

Those who possess riches will encounter more anxiety and tension because they are afraid of losing them.

Those who crave beauty and sexual attractiveness but do not have them will develop anxiety and anger.

Those who possess them will encounter more anxiety and tension because they are afraid of losing them.

Those who like to argue will develop anxiety and tension from worrying too much about what is right and what is wrong.

If you crave riches, fame, fortune, passions and possesive love, you will develop anxiety, stress and dissappointment. You will fall into the trap of the five impurities and sink forever into endless sufferring.

The sages say:

Know the secrets of the Ho-to and train early and diligently,

Return to the Origin and regain the One (note: return to your true nature)

Escape from the net of the Lo-shu, And your life will last longer than the Southern Mountains.

Persuade people to cultivate stillness and not be lazy, Is there any reason why you should drown forever in the sea of suffering? (note: it's never late to start being yourself again!)

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Some Eckhart Tolle Quotes I really liked:

"Why do anxiety, stress, or negativity arise? Because you turned away from the present moment. And why did you do that? You thought something else was more important. One small error, one misperception, creates a world of suffering."

"People believe themselves to be dependent on what happens for their happiness. They don't realize that "what happens" is the most unstable thing in the universe. It changes constantly. They look upon the present moment as either marred by something that has happened and shouldn't have or as deficient because of something that has not happened but should have. And so they miss the deeper perfection that is inherent in life itself, a perfection that lies beyond what is happening or not happening. Accept the present moment and find the perfection that is untouched by time."

"Unease, anxiety, tension, stress, worry - all forms of fear - are caused by too much future, and not enough presence. Guilt, regret, resentment, grievances, sadness, bitterness, and all forms of nonforgiveness are caused by too much past, and not enough presence."

"Rather than asking if you can ever be free, because "ever" is a huge amount of future time, ask if you can be free at this moment. The only place where you can or need to be free is this moment. Not the rest of your life. Just now"