oh leasha, it can be so hard when there not sleeping properly and you arnt either.

everyone has given you such wonderful advice, i'm just going to throw a few other ideas out there...
have you thought about going back to wrapping/swaddling then putting Jaz in her cot to help her self settle better?
has she ever had a dummy? a mother in my mothers group introduced a dummy at 7 months for this very reason, i know its just going to create another problem down the track but it could be an option?
Getting her to take her day sleeps somewhere else is a good idea, like the pram or a sling, could help break the cycle.
How is she with her solids? could she eat a bit more during the day to fill her up a bit?
Would you consider trying to put her into a routine? Robin Barker has a good basic one in her book baby love, maybe that could help?

I know my suggestions are totally random, and i'm not sure how you feel about them, just something differant to think about i guess..
i really hope things get better for you, you really sound like you are doing a wonderful job, Jaz is very lucky to have such a good mummy!