I feel the urge to not go to my friends birthday.
Why won't you go?
I want to be alone.
Don't you think that sort of thinking is a tad selfish? Besides, you might have fun at their party!
Selfish my ass, I'm honest about wanting to be alone on my birthday.
It's understandable that you want to be alone. But I would think about how your friends going feel if you don't show up, I think this may give you the motivation to go to the birthday party.