Hun, your parenting skills aren't crap, she's just doing what 3.5 year olds do. Some are worse than others, that's all.

My DD has just turned 3 and I've been pretty lucky *so far* - yes, she has tantrums but they are only occasional and never that bad.

My best friend has twins 3 months older and OMG, can her little girl put it on, and her son is worse at times!

It will end, as Erin said, I've seen friends' children go through it and when they hit 4, 5 they are like different kids.