Annette, I gained 57 lbs with my baby!!! And I am only 5'1...talk about feeling like a beached whale!! After trying for 10 yrs though I as soooo excited I didn't care at all. (And lost it all within 4-5 months) Sleep is your friend right now, and get all you can before the baby comes.
Not sure if you mentioned this yet or not-are you finding out what your having? Are you sharing if so?