Just adhere to your basic principals and be flexible with the rest.
My dd was a reeeeeeaal challenge as an infant and there were many days I wanted to run away from it all. I wondered why I had chosen this life. I missed adult company, I felt used and abused by this little person...
She eventually taught me how to raise her effectively, and I have to agree with everybody here who has said that GD is easier. OMG no comparison! I was in a power struggle with an iron-willed child and it was hurting us both.
She showed me what she needs, and your son will, too. You'll find what works and it'll be second nature and you'll barely remember this time in his life!
In the meanwhile, don't pay any attention to any of those annoying moms who behave as if there's something wrong with not finding motherhood, in and of itself, 100% rewarding. You were on this earth a long time before you had babies,and you'll always be much more than your childrens mother. There's NOTHING wrong with needing a break, NOTHING wrong with having needs of your own, and NOTHING wrong with having days where you want to go on a mommy-strike... just as long as you know you have to go back after you calm your nerves, and find a real solution. Your kids are not going to grow up unstable because you weren't a perfect mom, even when they were throwing stuff at you, so let yourself crack up every once in a while. Is it ideal? Of course not. I'm not selling it as a good idea, but when it happens, forgive yourself and move on, and redefine what works and what doesn't as time goes by.
It's a whole lot worse to stick to a rigid standard when it isn't working... and to make yourself nutso, to boot, right? As long as compassion is your cornerstone, you can afford to try whatever you need to try to save your sanity and your family's peace. Just don't forget what a big part of the equation you are! If you're not rested and feeling well emotionally, you can't expect yourself to help your ds grow. And if you need a break from him sometimes, give yourself that break. No, nursery school isn't going to solve whatever issues ds is having, but it may give you time to refuel so that you have the energy and DESIRE to figure it out.
Take care of yourself, Mommy!