What to do when your friend is hot and cold?

My friend is back and forth good and bad. She is happy then grossed out, I don't know how to please her! We went to camp (i am a tomboy) and every time is got dressed it was "you smell" "take a shower" "you wore that yesterday". it was like a game of ping pong! first off, I took a shower everyday. there was no reason why she would tell me I smell. back to th e story. So we were at breakfast and she was all nice to me, walking with me, talking with me. Then some kid knocked my milk all over me. All the sudden my friend went back to the "you smell"! She embarrassed me the whole 2 weeks calling me a dirt bag, and what not. So after she is done, she is my friend! I DON'T GET IT! I try and try, but nothing pleases her. She never feels good for you either. NEVER. If you told your friends you were going on a trip they would be like "that's so cool!" "have a good time!" or "that's amazing, send me a postcard and pics!" yea, you are not getting that with her. with her it is "what class are you flying?" "I have been there twice" or something rude like that. Then other times she is super nice. HELP!