Depression normal?

I just hit 22 weeks and I am so depressed and I have no idea why!! I am so blessed to have my little baby in my belly but I still worry and feel so upset and just exhausted constantly. I dealt with depression all growing up and I didn't think I'd get it now but I do. I don't even want to move out of bed to go to work and my whole body is sore and tired all the time like the beginning of a cold I thought maybe I was just getting a cold but it's been happening for over two weeks and I just am not motivated to do anything anymore I don't even want to leave the house ever where as a few weeks ago I couldn't stand staying in the house too long :( anyone else feel like this? When does it get better? I try and think about my little baby boy and it helps but I really feel like I have no control over it anymore