Oh Leash, huge hugs, it's very hard. But I can tell you that things get better
Astrid has some great suggestions. She really helped me (as did Christy) when I was looking at my
DS's sleep issues. Since finding that
DS is intolerant to dairy, soy, and nuts, as well as being sensitive to salicylates and some food colours and preservatives, and subsequently removing those things from his diet, his sleep has improved enormously. I'm not saying that Jazz has all those issues

, but just that diet (hers and yours) can have a huge effect on sleep. My
DS is by no means the best sleeper in the world, but he is sooooo much better these days. He doesn't fight sleep nearly as much as he used to, and the frequent (and I mean FREQUENT) wakings have subsided. And I didn't need to wean him

, we still managed to keep BFing until about a month ago. He would still feed overnight, but only once maybe twice, and not every night. And by about the time he turned two night feeds were fairly infrequent. TBH, his sleep is even better since weaning, but it's not something I would have compromised with until he was two. And I'm very glad I didn't as BFing actually helped us more than hindered us in his second year

.
It's a hard road, looking at food senstivity, if it is indeed contributing, but it is sooooo worth it, for all of your sakes. Sue Dengate's site is a great start. Maybe you could think about keeping a food diary, for Jazz and yourself, for the next couple of weeks. And then keep a record of her sleep (or lack of). That might give you some idea where to start. Remember that different foods, or chemicals, process at different rates, the reaction is not always immediate, in fact it often isn't.
Hang in there hun, things will improve. And in the meantime - nana nap!!!!!!