Lately my friends haven't been inviting me anywhere. I have been left out in every which way & i am getting really tired of it. I just want to feel like i belong, but i keep getting this feeling like they don't want me. Whenever it is someones birthday and there is going to be a party, they never tell me. I usually find out by seeing pictures posted on the Internet, (face-book). They talk to me at lunch, but they never wait for me, they wait for each other, but leave me to walk there all by myself. I always go out of my way to be nice and listen when they speak, but when i talk, it feels like no one is listening. I don't like not being heard because it makes me feel small.
I never let my sad feelings show when i am upset at them for changing their plans at the last minute when they decide that they would rather not hang out with me on a Saturday night. I take initiative and make own plans with them, but then they never include me in anything.

What did i do?
Am i not being a good friend?
Is it me?