Quoting Tiger Lily ♥:" It's bloat, girl. Your baby is smaller than a lemon and probably not out from behind the pubic bone yet. I am 22 weeks and haven't gained any, if you're speaking about ONLY gaining 10 pounds."
Just to be clear here, water retention adds weight. Also, she did say that the only thing that helped her nausea was carbs. Those are BIG in the weight gain department if a person isn't eating enough protien and getting exercise.
She could very well have gained 10lbs by now. With my twins, I didn't actually gain that much early on. I gained a total of 20lbs with them start to finish. (barfing and no room to eat)
With my son, I bloated like a PIG and gained 15lbs by 20 weeks. I gained a total of 25lbs with him but still, it was rapid onset of weight gain but it was mostly water retention.