Been friends for 10 years and fighting alot =[ please help?

So for the past 6 months my bff and i who have been friends for almost 10 years, we are 16. have been fiighting ALOT. we are with each like 24/7 but we vent behind each others back, and i found out what she said and she got pissed and said she still wants to be friends. i love her to death and we are like sisters but for the past 6 months this is what has been going on! i wnat to be friends but are fights are getting worse. any ideas PLEASE?