I don't know much about it but I would imagen it's not too uncommon with all the hormones running through you all bets are off when it comes to feelings. I would just talk to your Dr just to stay on top of it. Hope you feel better.
I am depressed alot throughout my whole pregnancy it's pretty normal just let your doctor know and just be prepared for possible ppd after you give birth
I had that with my first last few weeks I was either angry I was still pregnant or crying cause I was. I told my sr and he said it was due to hormones and just being so darn uncomfortable I couldn't even sleep.
He suggested pampering myself, pedicure, haircut etc... that and girl days helped a lot.