Weight gain!!

I was around 145 when I got pregnant and now I weight 202.. wtf?! I have been tracking my calories and watching what I eat and I don’t drink soda I only drink tea and water I don’t understand.. & I go on 40 minute walks 4-5 times a week.. I’m 35 weeks right now. I’m 5’6 it’s all mostly in my thighs and back. My stomach has obviously gotten bigger but my arms and face have gotten swollen too. I don’t understand where all this weight is coming from?? I’ve always been able to eat whatever and not gain any weight. I eat the same things I ate before MINUS excessive amounts of sweets and unhealthy foods like I used to. If anything I eat BETTER than I did before. What is going on?? Is/Did anyone else go through this? I’m so scared I won’t be able to lose the weight back and I’ll be stuck at 180lbs..