Don't be sad !!! Everyone goes through phases of feeling lonely and that's okay :E there's gonna come a day you will wish you have a day to yourself so you can listen to awesome music and dance in your kitchen to cheesy 80's music. So you should do that now while you have the chance. GO DANCE IN YOUR KITCHEN ... Now ! ;)
Why do I feel like no one wants to hang out with me? It feels like everyone has their own friends and don't care about being friends with me, I don't have any friends at all and I'm sad:(
When your personality and your attitude reflects gloom and doom - think Eeyore here - it will drive people away. I'm not saying you should be happy all the time, but it's your attitude that will attract people to you.
Smile a lot. Make eye contact - ask people how they're doing - did they have a good weekend. If you're still in school, look into joining a club that interests you. It will bring you in touch with people that have similar interests. If you're in church, see what the other kids are up to. Reach out. You'll be surprised if you can turn the attitude around, what will come back to you.
It sounds like everyone else dose not know what they areis sing by not asking you to come along.