From my personal experience: Get to know yourself much better, for real, and learn good habits to cope with your feelings.
Reevaluate your values so you get a healthy ones that will make you feel good about yourself; while also having certain degree of progression. Your thoughts, words and actions have to have a degree of concordance to feel really good.
Expand your universe and practise; play, watch, read anything that enrichs your inner world. You can't do this unless you do all this in a very pro-active way.
Think about how to get out of your comfort zone, gradually, doing things that you come up with or following advices from those you trust for real.
Get in touch with the outside world, slowly, with progression (like, stepping out of the comfort zone).
Don't hesitate to make adjustments about your private life and who you let in, without being rustless. Don't blame others too much even when you start realizing some obscure things about the true face of certain individuals; but realze that you might have to turn your world upside-down in this aspect. What i can tell you is, you need people close to you that know the real you for real; and that know that you might evolve and have progress within yourself; you'd want to avoid those that think they know you but really don't, and won't ever change their mind about what they think despite what you tell them (those are two different things)
Also, try to find someone that kind of have high levels of emotional intelligence and that have gone through the same stuff? or something alike, but, for real, in a way that you can see everything is real and there's validation from other people. (This is somewhat hard and it's usually unexpected when it happens, like, you naturally become friends with someone like this).
In general, get in touch with mindfulness and awareness, but in a way that's grounded (no "awakenings", the secret, and such; the law of attraction is crappy and can create monsters); learn to meditate, do martial arts or some kind of sport; take things costantly with the mindset of trial and error (but not being maniatic about it; keep it balanced). Learn a lot, about anything that interests you, put it into practise.
Those are some advices from my long, never ending journey ^^
Edit: Also, think about depression or any "condition" associated with overthinking like a sign that you need to get in touch with a more real version of yourself and with your surroundings. Normalize it, don't blame yourself for it and see it with accepting eyes; don't try to convince others too much about how they should treat you because you can't control how everybody sees you and how everybody treats you, but you can make evolution happen in your insides^_^