What is wrong with me?

What is wrong with me?
every guy i like tends to end up falling for my sister or a friend of mine. Am i really that unlikable? I just don't understand..is there something that pushes them away? honestly this always happens.

I was talking to this guy i have liked for a while..we would text every night, flirting and what not. Then one day he wouldnt text me back. I was fine with that i mean there are some days i dont want to text either. But this went on for over a week. When i finally asked "do you not want to talk to me or something?"
his reply? "Thats the point in me not texting back"
what did i do? did i say something wrong? I didnt even get an explanation.
that was over a month ago......we have yet to talk.

could someone please explain to me how.....man i cant even explain this, but how could one person be that unlikable. I mean I've been told I'm pretty and everything else. I can be friends with any one, but this always happens.

what is wrong with me?