A.F.
In a word - Yep. You gained too much too fast. I made that mistake with #1 and less so with #2, currently on #3 (26 weeks prego). What you can do is just slow it down by eating sensibly and getting MOVING (exercising -- whatever that means to you and what your OB has OKd for you). You can gain 1/2 a lb to a pound a week for the rest of the pregnancy and have a healthy baby but unfortunately you cannot and should not halt your pregnancy weight gain altogether or risk hurting your baby (and your own bones and mineral stores). You have 17 weeks to go, so your goal should be to gain no more than like 17 MORE lbs...yeah I know - you will feel huge (and could probably be AOK with gaining more like 9 more lbs). Talk to your OB about your concerns and if you are having swelling (like water weight gain with swollen ankles, fingers, face, etc) and not just fat gain, contact your OB right away because it is a sign of preeclampsia/toxemia.
Best wishes on your new bundle of joy and next time....watch the early weight gain :) Live and learn!