I´m loosing my best friend

I’ve been friends with my mate since primary school, but just recently she’s started to go off a lot with a girl called Debbie. Even when I want to be alone with my friend, Debbie always shows up. My mate says I’m her best friend and Debbie is just a pal, but I’m not so sure. The problem is, Debbie is really nice but I can’t help thinking she’s coming between us. I know this isn’t a big problem and I sound selfish, but it’s really getting me down. I keep having headaches when I think abou it.

Cathy