Unreliable friends

I think I've ignored the reality that some people only are friendly with you when they need your help. It's unfortunate, but also confusing:

I've known this one girl since the start of high school and we've never really hung out but she's always asking for my help and wanting to "check her answers" if we ever have the same work. However, even if we don't have the same things to do, she'll always invite me to sit with her or give me a hearty "hi" whenever we see each other. I think this stems from the fact that we met in the first day of Grade 9, but I really don't want to believe that she's just using me for help. She's a friendly person too, but we really don't share any interests or links other than the fact that we went to the same high school.

There's also this one girl who was in the same class as me last term, and out of nowhere this term decides to talk to me. It became really obvious though that I was her work checker because she always has to talk to me and see if my answers for a test match hers, or if the stuff I did last term might help her with the stuff she has to do this term. I've accepted that it's a purely academic relationship.

Whenever I plan something like a get-together, then my friends will cancel 50% of the time. Apparently, they forget about it or have "prior commitments", and I usually end up getting more excited about the day than I really should. My best girl friend is rather flakey and comes half/a quarter of the time, but when she does come, she really enjoys the experience and we all have a blast. I really have to get totally excited and plan the event months in advance to make sure that it does happen. I'm hoping my plans to head to Wonderland after exams will pan out. In this case, these are good friends of mine, and I don't believe they rank me "low on their priority list."

One of my friends who I have always invited to things has only shown up twice in 4 years to things I have planned! On the rare occasions that she has something planned, she will invite me and I go anyways.

I hardly get invited to stuff because I'm not really a "party" person and my friends aren't good at planning things anyways. I usually end up being the coordinator for things as well.

Jam it back in, in the dark.