Crazy weight gain?!?!?

Nicole • Second baby due in November 😍💕💙😊
Okay, I'm only 24 weeks but at my last doctor's appointment I weighed in at 183 lbs!!! I honestly don't know my exact weight when I became pregnant because I was struggling with losing weight around the time of conception but at the first appointment I was already 12 weeks and weighing 152. I've gained 31 lbs in 12 weeks!!! None of my clothes fit and I feel HUGE!! Not to mention all the back pain that comes along with it!! Stretch marks are rapidly appearing on my hips and butt and I'm going crazy!! I eat very well and swim an hour everyday plus walk at least 30 minutes a day but somehow this weight just keeps piling on!! I know you're supposed to gain weight while pregnant, but holy cow!! If I've already gained 30 lbs, how much bigger will I be getting??? I don't want to end up with gestational diabetes or have any other kinds of complications from it for me or baby. Please let me know of any advice to stop gaining or to even shed some lbs. I feel like it's unhealthy during pregnancy to gain so much so fast. Thanks in advance!!