Feeling so depressed today

I'm not sure why it just hit me, but I feel so sad/depressed today. I really miss my baby. I miss being pregnant, and being tired and all of the wonderful things that came with being pregnant. But its all gone now, all of it. I feel like I did before I got pregnant and that makes me sad. Its as if nothing ever happened. I have been doing so well until today, not sure why this hit me today; very weird.
I'm in my 2nd week back to work since the miscarriage, and things have been going great, but every once in a while it hits me. I miss my baby so much. That really about sums up my current mood. I feel empty today, and its very possible that this is all coming out because I started feeling like AF (aunt flow) was on her way. Every cramp is just another reminder that my baby is gone. I don't understand this world sometimes, and I hope someday I do.