do you seriously think you might be really not doing very well?
because, yes, I often feel like I'm doing a lousy job. Like today, ds, who is 2.8 and has been potty trained for about 5 months, decided to pee on my 5 page, hand drawn assigment that was due in. because he thought that would be funny. And my god, did I shout at him! At times like this I know I should probably sit him down and say something along the lines of "Mummy loves you very much but she is not happy that you peed on her drawing, that made mummy sad...yada yada..." but in all seriousness, I am human and I was furious that I have to redo all that work. That happens, to at least 98% of mums, and I think must be nearer 100% of mums of 2.
But on the other hand, if you think it is more, maybe you need to talk to someone outside. Why is it they don't brush their teeth or hair? Is it that you feel too tired with it all to bother? It could be that you're depressed, or just emotioanlly completely drained.
So just cos you're worrying doesn't mean you're not doing well, but that doesn't mean there isn't something there that needs sorting.
Emotional stuff is the real key. You can get away with all sorts if you honestly and truly keep good comminication going.