Sleep Troubles

My cousin gave me the book "Baby Wise" for a shower gift. I read it all the way through twice before Cort was born, and I was determined to follow it once he was born. I was going to be one of those lucky moms whose baby sleeps through the night from early on.
Once Cort arrived, I made sure to follow the book, which basically says that your baby should eat till he's full, be awake, and then fall asleep on their own. Well after a few months of following the book Cort started to sleep 8, 10 and 11 hours straight. Yea- I did it.....WRONG.
At five months Cort fractured his skull. I was so paranoid that if I left him in his crib he would bump it again and do more damage, so I made my first mistake and brought him into my bed to sleep with me.
Then Cort got a really bad cold, and was just plain run down, so I let him fall asleep nursing- mistake number two.
Since then I put him back in his bed, but he would only sleep three hours or so at a time before waking up and needing to be nursed back to sleep.
Then this past week he started sleeping even worse, and he would nurse for hours at a time in the middle of the night.
I've decided that I have to break his need to suck. So I have decided to try the method where you put them in bed sleepy but awake. Wait 10 min. then go in and pat his back and reassure him. Go out wait 15 min. go back in, etc.
Last night was my first attempt at this. It took 45 min. And man was it hard. I am one of those moms that has a really hard time listening to my baby cry. But I think he really needs to learn to sleep on his own.
He cried for 35 min. this morning before falling asleep for a short 30 min nap. I let him cry for 1 1/2 this afternoon, before finally just getting him out of his crib, since he refused to sleep.
I really want to keep trying but I am so frustrated. This is HARD. Someone please tell me it is worth it and that in a few nights Cort will be able to fall asleep on his own!