past present

People say don't live in the past and don't worry too much about the future if you want happiness in your life.
Can people really do that ?
Because I can't. No matter how hard I try. It keeps coming back to me. I guess I am not strong enough. I'm weak. But giving up is not in my dictionary. I will always try and try and try and pray and pray because I wanna be happy like everyone else. I do fail. In fact I always fail. There were days I wept hysterically and until today I still do that just to let it all out. I wanna be happy. I really want to forget. I dont wanna hate people even those who had gave me shit. I don't wanna hold grudge. It's eating me up. I wanna be happy. I wanna be free. I pray. Allah help me !