Anti social or an introvert?

I can't tell if I should consider myself to be anti social or just an introvert. I avoid people when I go outside, decline offers for parties/celebrations/get togethers, etc, and I'd rather be by myself just like an anti social person would do. But as an introvert though, I'm shy and even though I'd rather be on my own I wouldn't mind company as long as it's not for too long of a stay and as long as it's with close friends (that barely have), and I get tired after being at a social event, if I even go from being forced, and I feel much better after coming home to my sweet solitude. What do you think?