I agree with everything sarahm said! We did about 3 weeks of transition visits (starting for 30 minutes with me there) graduating up to T being there for about 3 hours, having a feed and a sleep.
I also started him a week before I went back to work. I was a blubbering mess the first day, so it was great to be able to go to a friend's house for a coffee rather than work! Also, it's nice to have some time to yourself before you go back to work
Good luck - it's a hard adjustment initially, but it does become easier and before you know it, it's just the norm.