Swelling or just getting fat?

So I've gained a decent amount of weight this pregnancy (started at 119 and now I'm 150). I haven't been too concerned about the weight since I'm 5'6" and should actually weigh 140 normally. Anywho, Ive noticed that my feet, legs, and ankles are getting quite... plump. They don't feel swollen or anything and my doctor keeps commenting on how impressed he is that I'm not retaining water. So does this mean that now my weight gain is manifesting into my cankles? Because it's boot season here and I can't hardly get my feet into my boots without them expanding 😫