This much weight gain can't be normal?

So in the past 2 weeks I have gained 15-20 pounds🤦🏻‍♀️ I had a OB appointment 2 weeks ago and my weight was like 150-155 somewhere in that area. I haven't checked it since then till right now. I have been doing a lot more here lately helping my mom clean houses and stuff these past 2 weeks and thought "hey why not check and see how much weight I've LOOOOOOSSSSSTTTT!" And BAM slapped dead in the face for some reason I've packed the pounds on 🤦🏻‍♀️ I will be 36 weeks this Monday and also have a OB app this Monday to and I already know he is gunna complain about this. Why would I have gained so much so fast??? I've noticed a lot of swelling in my legs feet and hands the past few days and thought that is was just a pregnancy symptom but since have seen how much I weigh I feel like there is something els wrong. My pre pregnancy weight was 135 and like I said 2 weeks ago I was like 150-155. So now I've gained more 😫