you are a tool that is being used.

your first assumption was a correct one. the girl is using you for your talents in getting her through the class, through the loss of a boyfriend, lunch, etc. drop her and move on. let it be. don't become one of those pathetic losers who hang on and give, give, give without any receiving. there's plenty of those pussies in this life without you adding to the tally. you were used, learn from it, and forget her. and just another thing: don't go overboard with the affections for women these days, it's best not to invest so much so early in the "relationship". you gave it all, she gave back nothing, now you're the one begging for answers. don't put yoruself in this position again. learn your lesson!