Best friend problem!?

So i have this best friend who I've know for 10 years and we have always been BEST friends almost like sisters. I'm two years older than her. I went into high school this year and shes in 7th grade. The last 6 months we havent talked. Her friends are really mean to me right when we first meet. So i stopped talking to her. We sort of made up, i guess were in the middle of it. But i invited her to my bday party and she said no because she had other plans but she forgot about my birthday. Then she invites me someplace and im mad at her so i say no because she wouldnt of invited me unless i hadnt invited her to my party. Then she tells me how much she loves me like sisters! I have no clue what to do. I don't really want to be friends with her if shes like this but we will always be close(she lives next door) and her parents are my second parents. Please help what should I do?????????