Going back to work

My little man will be 12 weeks old tomorrow, so next week I have to go back to work. I'm getting so anxious about it. Not sure why... This is my 2nd baby.

I'm only working one day a week, but agreed to be the as needed person when possible. My manager called yesterday and said my coworker had emergency surgery and needs help covering her shifts. So I'm working all day on Monday. I have not been away from baby for more than like 2 hours. The money and the adult company will be nice but I'm so unbelievably anxious I don't know what to do.

My husband will be home and watch my boys. He has to take my older son to the doctor on Monday and I've never missed any of his appointments.. I feel so guilty..

Any advice on how to work through this?