Why am i doing this, whats wrong with me!?

ok ao this kid Robbie and I dated over the summer and everything, then i dumped him because i thought it would get awkward considering we're on the same swim team (im the only girl). i see everyone there as my brothers and dating one of them just made it weird. well after months and months of awkwardness we finally came to terms and are talkng again. the only thing is, he likes me again (he told eric who told me). when we talk, he pisses me off, i dont know why but i get so angry! but then when he doesnt text me or anything... i miss him... why am i thriving on him?! i cant stand talking to him when i do and want him to move on but then when he does i want him to come back! whats wrong with me?!?!?