They Don't Call it a Transition for Nothing
Going from full-time mommying back to work might be a big shock at first. You have months of missed events and changes in policy to catch up on. There may be new faces to get used to -- and some who are no longer there. In general, you're bound to feel a bit out of the loop, afraid that you've missed some opportunities or even that you've lost some of your skills in your time away.
The key to keeping your sanity is giving yourself a break. Think of your time back as a trial period -- give yourself 90 days to feel back on track. No one (including you) should expect you to be back 100 percent on your first day. You need to get back in the groove first. Not to mention, it can be really, really hard to leave your baby in someone else's hands, even if you're excited about going back to work.
If you can, have your first day back fall on a Wednesday or Thursday, so you're not there the whole week. Another good idea if your child is going to be in daycare is to have him or her start half-days before you go back work. That way, you and your child will both be used to the idea and you can have a little extra time to prep for your return.