Weight gain already at 5 weeks

I am already becoming obsessed about weight gain because I don't want to gain as much as I did with my first pregnancy. I didn't loose the last 10 lbs and right before TTC we were on vacation so I gained an extra 3 lbs on top of that. So I am 5"4 and 140 lbs starting. I continued to eat usual, pretty healthy and nothing extra, I weigh myself this morning and 142. What the hell!?! I'm only 5 weeks. I figured since I was a heavier starting weight I would have a slower weight gain than my first. My boobs went from B cup to DD, would that do it?