Weird actions??????!!!!!!!!?

ok so lately my friend (let's call her blue) has been acting strange and kinda bratty. like 2 days ago i said to blue and my other friend "it would be really fun to switch lifes for a week" and blue said "that wouldn't be fun for me because i love my life"....that's okay, i guess i'm sensitive but here's the second thing, recently, in math cl she'll ask me for help and i say "well i think you do this...well actually i'm not sure...sorry". and then she rolls her eyes and starts competing with me to see who can get it done faster/who's smarter. WHAT'S THE DEAL? geez, i hate having a competitive friend