Best advice from working mommies whose babies go to daycare?

I will be returning to work this week and my 3 month old son will going to daycare 5 days a week. I feel very good about the daycare we have chosen and logically know that in the long run it will be good for him (and probably me!) but for now I feel like a piece of me is being ripped away and I am wondering how I will get through without constantly crying! Would love to hear from others who have successfully returned to work and feel good and comfortable about their baby and the daycare experience.