Sexual anxiety, apprehension, shame. Help.

Hi, so here's the deal: I'm a 22 year old male and haven't had sex in nearly 4 years. I drunkenly lost my virginity as a freshman in college and had sex with that same girl once more a week later but since then no sex. I have gotten a handjob since and a few months ago I received my first blowjob which wasn't great. The reason the bj wasn't very good was because I dissociated myself from the situation and lost interest in it, I didn't finish either.

So, nowadays I find that even masturbating isn't all that pleasurable and I typically feel ashamed of myself afterwards. I obviously still get horny but immediately following the release of that energy I regret it and feel disgust. In social situations I'm very normal and don't have trouble talking to girls but I can't help but feel that should anything advance sexually between me and a girl that I wouldn't be able to perform due to nerves. Before anyone asks, I was not sexually abused in my youth.

I'm not sure if this is the right subreddit for this but I'd like to hear some advice or even just hear your thoughts on this and hopefully someone has gotten through something similar. Thanks.