I too feel exactly the same way as you do. I have a three-year-old daughter who has temper tanturms when I tell her that she can't have or do certain things. She screams at the top of her lungs, throws things, etc. I too enjoyed her while she was an infant but once she hit three, everything changed. I'm a single mom and I suffer depression big time. Her father is a good for nothing, selfish, drug user. I made the biggest mistake of going with him. I also get very frustrated when my daughter acts this way. Sometimes I want to hit her or worse then I have to give myself a breather to calm down. I think most of this anger is also towards he dad as well because I hate him so damn much.
I also noticed that when she is with other family members, she doesn't misbehave like she does with me. She is excellent with my mom. But no sooner my mom and I are together, that is when she acts up. I wind up getting mad at her and in the process, my mom fusses at me, defending her, which I think adds on to the way my daughter acts. It's like my daughter turns my mom against me. And believe me, I feel more depressed afterwards. Sounds like your son and my daughter have alot in common even though they are not the same age.
I also read someone else's post about being a single mom and feeling like you weren't good enough for you kid and that he deserves better. I to also feel this way alot. I feel like a bad parent that is not even stable enough to take care of a child because of my mental illness and my medication I have to take. I think that everyone will make fun of her and tell her that her mommy is crazy, etc.
WOW!! This posting really hit home because I thought I was the only one who felt this way about being a parent. I feel alot better knowing that I'm not the only one who feels this way about my kid.