There's this guy i've been talking too on and off for about 2 years and we only met twice. but i like him, and?

i dont know why. the most recent time we saw each other was this past march and it seemed like everything went well, like there really wasnt a dull moment. i had a good time, and i was thinking he did too, but ever since then he hasnt really made any kind of effort to talk to me, or see me again. and everytime i try to talk to him it seems he doesnt wana talk or he just doesnt answer. now its been 3 weeks since i last spoke to him, and im going crazy because all i do is think about him but im tired of trying so much and him not giving an effort back. now a part of me is telling me to give up on him and another is telling me not to give up....i dont know what to do