big hugs to you!!!!!sounds so much like DD!! at about 5 months she would lay in her cot and coo and chat for a min then be asleep!! then slowly but surly it changed and got harder and harder, progressing to hours of rocking and patting and laying and in my head swearing!it got to a point by 12 months that id go in to put her down at 7.00 and i wouldnt be out till 10!! then she would be awake again by 12! and it started over...i swear at times it was harder than having a new born!!!
I wasnt interested in CIO or CC so i just had to stick it out.but i know others who swear by it. shes pretty good now but i feed her to sleep and if that fails i lay down with her (she is in a big bed now) and pretend to be asleep and that works, sometimes after five mins, sometimes an hour!
i totally understand your frustration though! i had my moments when i just walked out and left her to cry, just to gather myself! sometimes you just get to breaking point.
have you got a good night time routine? DD improved when she dropped a day sleep, but i think hes a bit young to go to one day sleep. other than that...hope you get some good answers....and more sleep!