People are unpredictable. Don't take it as a judgement of who you are, we all face rejection sometimes. It can even be good for you in doses because it helps build resilience and shows that failure is just part of growth as a person. If you never fail, you aren't trying hard enough.
All you can do is sincerely try, if you are doing that, as well as accepting feedback and growing, the right people will notice that effort. You'll find your people, just don't stop trying.
I also suggest meditation, it can help you to identify the roots if thoughts as well as help you to know yourself. You may find the root of your negativity if you explore yourself.
Not an ad, I use it regularly, Headspace is a great app as an intro to meditation. Costs like $100 a year I think? If money is tight there are plenty of free alternatives.