pregnancy symptoms gone!?

This is my first pregnancy and so far has been a very anxious one! The first 12 weeks were very difficult and I've had lots of time off work due to depression and anxiety due to work related stress (suffered with it before but doctor thinks that becoming pregnant and my change in hormones brought it all on again). Thankfully I'm starting to feel more human again and haven't been so low and emotional over the last couple of weeks and I feel much less anxious about my pregnancy and am in the process of trying to get back to work. During my first 12 weeks I also had many physical symptoms - belly aches, sickness, headaches and incredible tiredness. I also seemed to be developing a bump a couple of weeks ago (which I was thrilled about!) but it seems to have stopped/disappeared?! I know I should be pleased that my symptoms have eased but I'm worried about my symptoms disappearing particularly my belly! Anyone else experiencing anything like this?  I'm 15 weeks tomorrow.