most of the dietary stimulants (like hydroxycut) are herbal caffeine equivalents. They are not going to affect your birth control pill.
I would like to point out that you are young and there is no 'miracle' pill to take that will make us loose weight. The only absolute way is to decrease caloric intake and increase physical activity. Prolonged use of stimulants (like hydroxycut) may have life long consequences such as high blood pressure, heart irregularities, etc. For that reason, as well the lack of FDA proven evidence, I do not condone the use of these types of supplements.