Sex issues. . .

Hi.

I am 16 years of age, and have a lack of sexual desire.

I have only slept with one man, and he is still my present boyfriend. We have been dating for nearly 2 years.
We are both very worried about my problem, and don't know who to turn to for help.

Sex just doesn't feel "good" for me, in the orgasmic way. I very much enjoy the intamacy of sex, and the closeness of us together.
There is nothing wrong with my partner physically, so that, I know is not the probelm.

I am also quite overweight for my age. I weigh 80kgs. Could this be the problem??

Please help me!!!