Why won't she sleep?

Fiona is almost 19 months old, she has not slept through the night once, well the day of surgery she slept all night.
It's so frustrating, she goes to sleep no problem but she won't stay asleep, she wants to sleep with me, I want her to get used to sleeping on her own. Last night we both had a major breakdown, I was trying to let her cry it out, she started screaming at the top of her lungs, so I tried to calm her down by picking her up, well that didn't work, she threw herself backwards and was inconsolable. I started crying also. Keri came in and I yelled at him to get out, I had it under control, but I didn't I started yelling "Make her stop crying". I felt like she was a newborn again, I had all those feeling come rushing back, it was awful.
I don't know what to do, I'm so sleep deprived, I need sleep!!!