Missed a first

I am having the worst and most emotional week ever, and I guess I need to vent. I went back to work Monday after being home for 12 weeks. It is KILLING ME that I have to come to work and be away from my girl, but we need 2 incomes. I found out that yesterday (only the 2nd day at day care), she rolled over for the first time. I'm taking this really hard. I see moms on Facebook posting pictures of their little ones saying "I love staying home with my baby" and "no job could keep me away from my little one!" and it really hurts. If I had a choice, I would be with her every second. I feel like a scummy mom because I missed a major milestone. She doesn't really smile when I pick her up from day care... How do you guys cope with these feelings? Everyone in my family is acting like I'm crazy for feeling bad about this.