Been there in a way.
This is called being "Overcritical" of yourself.
"Dating Issues" are a real thing, it might seem like you are asking too much from life but you aren't.
You crave companionship and that is not a wrong thing to ask for.
But as I have been through a similar experience and was constantly worried that I'd never find someone who will appreciate me or love me, but life is strange, I found love, dated, had a breakup, made some pretty neat friends, guess all it takes is a little vulnerability and courage to find 'your' people.
If you like someone, let them know in a very simple and honest way, if they are not interested in you, they would let you know (they should) and you don't have to be disappointed, as you would find someone who will like you back.
And also, don't be too hard on yourself please, 19 is such a fragile age, It might get easier as you grow up, you start learning a lot about yourself and managing yourself better.
Also, try to quit Insta/FB/Snapchat, they fuel up insecurities.
You'll find your tribe, I'm sure