I'm 16 and I need help with my weight can anyone inform me how?

I use to weigh a lot when i was younger and i've lost over 30 pounds and had awesome intense muscular thighs. The only issue i have is my thighs aren't bad but could use help on working on them. They have a little space but are jiggly (Boys make fun of me saying I'm all skin and bones but i have some meet on my thighs..i disapprove their comments) I've tried a lot i eat healthy everyday and i exercise i gain muscle but then it disappears. I eat so healthy i actually count up my calories and get high 500s and low 600. WHAT AM I DOING WRONG THOSE LAST TEN POUNDS ARE KILLING ME!