Anyone else pretty fit and healthy and packing on the pounds?!

I'm 5'5.5 and prior to getting pregnant I was 125 lbs. Body fat was normal but low and I ate healthy and exercised often. Now, I'm definitely eating more calories, about 300 more a day, and working out about the same, but not as intense. Man, I am putting weight on crazy fast, I'm up to 140 lbs! Should I be doing something different?? I know I'm still a healthy weight for my height, but I don't know if this is normal because everything I see says I should only be up like 5-7 lbs. With all the changes going on though, 15 lbs doesn't seem outrageous to me lol.