resenting your kids

I don't know if I'm starting to get some late ppd if that's possible or what. But lately my 2 year old is making me so mad and angry about everything. It's making me start to wish I didn't have kids. I have 5 year old and a 6 month old who I'm still nursing. But lately all my 2 year old does is cry and whine about everything and I can't stand it. It's like the instant I come home and pick them up from daycare she starts. I'm getting so stressed and worn out that I feel like I'm not being a good enough mom to my kids because of her.