Help me i am getting worse each day?

i feel like nothing will happen good to me , last year i loved a guy ,a batchmate , i loved him so much , n knew dat he too love me but we never talked juz watch each other , i always waited for him , thought hes a bit shy. but dat was our final year, n now we all have separated to pursue our career though living in the same city, n i have got to know he talked to other girl of the same batch frankly some even make fun out of both, here hes not shy at all, but the problem is that i still think of him , n imagine him . i think i shud not think upon dis coz nothing happened, like i never shared my feelings nor he, maybe he had no interest in me , n look i dont even know, but i love him , he has nothing to to with me , hes happy in his life have friends n is having fun, but these things are not with me, my life is total empty, pls help i cant come out of my imagination, i imagine evrything dat has no relation to reality n is impossible to happen and its ruining me coz i cant concentrate my on studies. Pls Help