Hey, I have been on citalopram before. I'm on currently escitalopram which is literally a cousin next to citalopram. I have been on 20mg on both. Yes I have OCD too. So I understand where you coming from. The hitting thing. I dont know how that be OCD unless it's a form of ritual of coping.
When you mention how you can't get happy either. It can numb the emotions so that's probably what it is.
I would suggest talking to your psychiatrist about it, is the best option.