I'm feeling the need to end a friendship over how they acted during my birthday.
Did something happen on your birthday?
They made me feel miserable.
It's okay if you want to have a good time on your birthday. You should talk to  your friends if they harmed you. You might regret ending the friendship without trying to work things out.
That might just be what I need to get over them.
Like I said I would really take some time to think about if this would be what's best for you. A simple conversation may be able to resolve the issues between you two.