What to do if i have this crush on a guy but he absolutely hates me. what should i do?

Take charge: Forget him -- your "crush" is likely to annoy him and this can lead to trouble. You have a reasonable amount of control over you feelings. The cure for this is to seek out the company of other men with the expectation of finding another guy who will like you. Helena in "A Midsummer Night's Dream" needed magic when she was in this situation, and there's little of this in the real world.

A/W Dr Friedlander: Why set your self up for failure/ disappointment? If you desire a relationship - encourage you to look into one where there would be mutual positive regard.