I can't handle my emotions?

Recently I have been having some problems with my friends at school and I have been quite upset by it. But I also have been feeling really happy at some points - happy like crazy happy like wanting to spin around and jump up and down. I am feeling really happy one minute then something will happen and i will feel like curling up and crying and then back to the happiness again. I can't cope with the crazy changes anymore as it tiring. What could be causing it and how can I stop it???