I have two friends. One has been my best friend since we were 11 but then I moved away after a year and we kept in touch every week. As the years went on we chat less and less but we would still sometimes say hi to each other. But recently it was my birthday and she didn't wish me happy birthday. I am deeply saddened because I know she didn't forgot, not to mention I said happy birthday to her a few months ago. Should we just stop being friends?