i dont know how many you have to take for it to work, but too many or too few will just make you feel dreadful and you will be sick for hours (if not days after)
it's really hard to see when you feel so low, but your life wont always be like this. In a couple of years time you wont even think of her.
The trick to life is not to live it how other people do - do not conform to what society expects from you and you will be much happier. I'm not saying to brake the law or be a jerk. But just think about what makes you happy and what YOU want from life. If you're not sure then try things, find a nice band or singer you want to follow, get a pet, learn a language, go walking, buy a ps3, become a cross dresser. You will then find that you will probably meet someone that you really like and get on with. Also don't be afraid to cut people out of your life that are bringing you down or that make you feel s#!t