I feel the same way! We planned to get pregnant so I feel like I should be happy but I am full of mixed emotions. Maybe because its my first. I started seeing a therapist to help with my fears and it has helped a lot! I also started taking extra DHA because I read in several books that it is good for your baby's brain development and also for your own emotions. They actually tell people with depression who arent even pregnant to take it because it helps your seritonin flow. When you get pregnant, your baby takes DHA from you for its development and if you dont eat a lot of fish, which is where we get it from, you could become depleted of it. Ive noticed my mood lifting. Good luck
I think that is perfectly normal. Your hormones are just starting to get all out of wack and naturally that is going to effect your mood. It can never hurt to talk to your dr and see if they have any suggestions.
Also, delivery is a long way off; try to enjoy your pg for what it is right now.