it's really hard, when you're with someone you really like, to not fall in love. and it's really hard, when you love that someone, to try and be without them. you may not be able to sleep, you may think there's no chance of ever being with them (which sorry, but there probably isn't), you may think they're out of your life forever, and you may think you're destined to be a lonely cat lady. being alone sucks, and there will be tears (many) but in the end you have to think this way: is that person losing sleep over you? is that person crying over you? does that person worry about never seeing you again? probably not. why should you waste minutes of your life for them if they wouldn't do the same for you? don't, because they probably don't deserve it and might feel pretty bad when they see you can do fine without them (this is only a MIGHT, because they may truly just not have feelings). don't waste your love on someone else. because the only person who truly loves you, is you. and you can break your own heart, so don't even allow someone else to do it.
and who knows, maybe they'll come back (MAYBE).