You sound like me when I was 23.
"Not being able to wait and play it cool with a date, and possibly coming on too strong."
Don't be me and drink to loosen up. I drank to rein in my energy on dates. I woud constantly talk for fear of the dreaded 'silence' so I would drink to calm down. But eventually my drinking became the only way to function socially. My advice? Realize that you're gonna win some and you're gonna lose some. It's not the end of the world if she's not into you. Now I'm happily married.
"Posting pointless stuff on social media for the dopamine feedback loop of validation."
I had this problem. Broadcasting every one of my feelings and goals just to get a like or some kind of response from people. One day I looked back on a few of my declarations, with people cheering me on, only to realize I never accomplished any of them. Deleted Facebook right after and never looked back. I'm more private with things like that now.