Kellee, I did controlled crying with Ashlea when she was little, she was used to being rocked or patted to sleep which was fine when it only took five minutes, then it started to take twenty mins, then fourty, until every sleep time it was taking an hour to get her to sleep.
I did controlled crying with her, and it nearly killed us both! I think my biggest problem was that i was a stubborn nut and so was Ashlea, and I really should have gone to the sleep schools or gotten help with it, and it really makes a huge difference having support. Ashlea's dad worked night shifts, so i was home alone all night, and he slept most of the day so i once again had to deal with it then too. I did find that if he was up and there with me it was alot easier to deal with.
From what i know, controlled crying isnt the same as it was years ago. Its not about leaving your child for such an ammount of time til they are hysterical, but more so responding to them, reassuring them etc.
I have seen some kids that get it in one or two days, others take a week or two, and yes some kids never seem to get it.
I personally felt like if i couldnt deal with my own child and need someone else to do it for me then i was a bad mother too, i know how you feel...
The two hardest things for me was sleep deprivation, cause i was a monster without sleep, and hearing her cry and cry and cry thinking just shut the hell up and sleep you stubborn nasty baby! Then i'd feel awful for thinking that about her!
My biggest point is that it does work for some, not for others, and with the help and support from the sleep centres etc it would be alot easier and at least something that may help if your open to it !
Good luck!