I have no courage to ask a guy out that i like, that is relentlessly flirting with me. I'll find the smallest things, like how he doesnt text me, and think he doesnt really like me because of that
I am having the same thing too. When I am overthinking, I tend to be very annoying and bugging.
Anyway, OP, i have issues with my self image too but regardless, u need to step out. Yes, he might rejects you and trust me, you won't be as depress as you thought you'll be.