Pregnant and Worried

This isn't another post "should I lose weight." I'm well aware of the fact that I do and have needed to for a long while. I'll try and make my story short... A year and half ago I moved from Okinawa,Japan (Husband is USMC) and it turned my entire world upside down. While out there I had become a gym rat, but in the process ingured myself. Ended up with something called "piriformis syndrome". Believe me it sucks. Makes it difficult to do any type of activity without suffering horribly the next day. Anyways.. I had to slow down on my work outs.. which then of course dwindled to me not doing them at all. And boom.. Depression. 25+ lbs later and a mental institution later (manic depressive episode) I decide I want a baby. I'm super excited and couldn't be happier. , but apart of me is scared of the slight gain. I'm sitting at 188lbs. I'm 5'4 . Any advice on how to loose weight after pregnancy?