hate being a parent? normal?

So my son is 2years old and I just for some reason hate being a parent.... I feel horrible saying it but I do! when he was first born I fell immediately in love with him and don't get me wrong I still love my child to death but as he got older I started to get impatient and just loose my nerve so quickly and now I'm just at the point where I don't want to be around him i hate being a parent and i feel horrible for feeling this way and don't understand why i do. he never listens to me and constantly drives me up the wall I'm constantly having to yell at him and I know every one says it's just having a 2 year old but I'm so miserable half the time. do you think this could be depression or like post partum? I'm so tired of feeling like this...and his father is involved completely so I'm not by myself either that's why I don't get what's wrong with me.