Gain too much weight?

Bridget
My Doctor told me the other day that she wants me to only gain 15 pounds in this pregnancy. While I think that should be fine, I'm a little panicky since I have gained 9 already and I am almost 22 weeks (21/5.) Is it really feasible to only gain 6 more pounds the rest of the pregnancy?!? I started out a little overweight, nothing too crazy but I find myself obsessing now. I weigh myself every day. Anyone else having this problem?