Returning to work :(

Well on Monday I start a new job and will start working part time (Monday and Wednesdays 8:30-5:30) until October when I'll work full time all week. I am terrified I am going to cry all day on my first day of this job because it will be my first day away from my daughter since she was born 8 weeks ago. She will be staying home with my husband as he works nights so we won't need daycare. Any tips? I'm sure my new boss would understand if I cried as he is a parent himself and knows I've been on maternity leave that's why he suggested part time to ease back in to working. I will just be super embarrassed if my first day is spent tearing up because I miss her so much. I'm a very anxious person and cannot take my anxiety medicine because I'm breastfeeding. How would you handle this emotional day? I'm already crying and its 5 days away.