did i ruin my metabolism :(

i had an eating disorder for over 10 years [starving, binging, over-exercising, laxative abuse, diet pills] and got some help this summer... i finally started eating like a normal person in october and gained 25lbs! i have been dieting like crazy again for months and running 3 miles a day, but i can't seem to lose a single pound. when i was eating 1200 calories a day [and still running] i continued to gain. i also can't eat carbs without ballooning... i have been on a low-carb diet since i was 11 and i'm 22 now. i don't know what to do anymore :( did i completely screw up my metabolism, or do you think there is an underlying medical problem? everything i used to do that worked so well doesn't work at all now... but i have to keep doing it to stay at a weight i'm not even happy with! i work so much harder than anyone i know and it seems like everyone around me is successfully losing while i'm killing myself for nothing! my body does not reflect my lifestyle at all!!! any suggestions? i WANT to be able to eat healthy, but i feel like it's impossible without getting bigger and bigger :(