pregnancy weight gain :/

Im starting to get really self concious and down on myself. this is my first pregnancy, & although i know that its normal to gain weight, i just feel like im gaining like crazy, & i dont feel like im constantly eating. my starting weight was 265. so i was already overweight. ive never been over 300 pounds before i got pregnant there was a point where i was like 292 & i was like nope, not letting myself get to 300 & i start going to the gym, & got myself down to 245. but i went to my OB today and im now 315, at 34 weeks. last time i went i had only gained 2lbs between my 2 week visit. & this time i gained 8lbs. i just dont get how im gaining so quickly. during my 1st & 2nd trimester i was at school and on my feet all day, but even then i had gained about 30 lbs through the 1st two trimesters. but i graduated and in my last trimester, im at home all day while my husband is at work. it hurts my hips really bad to walk more then an hour, so its hard to stay active. i feel like I'll be really motivated to loose weight again after i have her, but im scared its going to be really hard after i have her. i have no idea how my body will behave after baby. im just getting more depressed about it, & i still have 5-6 weeks left. can anyone give me words of advice or encouragement?? i could really use it.