Gaining Too Much Weight?

First of all, I dont need a lecture on my age. Im 16, and this is my first pregnancy. I have gained like 25 lbs, and I am 27 weeks and 2 days along. I have several people I know who have been or sre pregnant but they weren't as big as me when they were 27 weeks. Ive been told Im "all baby"... but I feel huge and heavy. I have several stretch marks, and still have 3 months to go. Any advice?