Suggestions ANYONE?

I've about had it. My daughter Evelyn (3) has reverted way back to diapers. Almost two months ago, I got her to wear big girl underwear, and poop in the toilet. (Used a new care bear for her to earn to get her to do it.) She pooped for a week straight in the toilet. We used pull ups when going out. Suddenly now, she wont even consider going potty ever again. Throws a huge fit like I'm punishing her just to have her sit. I put big girl underwear on her today (staying home all day, thought I had the paptience to sit her on the toilet every hour to make sure she stays dry.) Sat twice, no luck. Then she decides right afterward to squat on my carpet and pee all over herself! I KNOW she knows how to hold it, and go in the toilet. I've used candy, toys and promised outings for rewards. She is not scared of the toilet, she just is determined not to do it. Suggestions PLEASE!!!