Growing up without a father

Hi guys!Well, I'm a 15 year old and my parents are seperated. Somehow, I'm living with my mum and its really hard.As you know, for a boy growing up into a man, having a father is really essential, for he is someone I have to look on to. However, now withour a father, I do not know how to you know, become a man, and somehow also began to look at pornography, which is a bad sign. I heard there are also negative impacts like becoming a homosexual, and I do not want this to happen to me. Somehow, my grades in school had also deproved. My parents became sepearted when I'm 12. So guys, I really want to know what I can so or what I SHOULD do. I really am at a lost, facing challenges of entering manhood is really not easy without any father in the family.