I feel like such a loser i'm never invited to parties and am always home.?

[Sweetie]

I'm 15, a sophomore in high school. I'm not a loser but i'm not extremely popular. I just you could say in the middle. The thing is though, i'm never ever invited to parties. Ever. My weekend usually consists of me staying home by myself on the computer, or going to a sleepover with my friends. That's seriously it though. It makes me wonder something obviously has to be wrong with me because i'm never invited to party like events. I'm not mean either i'm really nice to everyone but i think that people are just intimidated by me people have said that to me before. But seriously i feel like such a loser almost every week but especially today because its New years and i have no plans. Everyone else has plans except for me. I'm going to be staying home and my sister who is 19 has a party to go to. What makes it worse is she asked me if i'm going to a party tonight and i had to lie and say that i had a lot of homework and i'm really tired instead of revealing that i wasn't invited to any. The thing is though i know that people i know are throwing partys i see it on twitter but no one bothers to invite me. It just makes me sad