Before I had kids, I always thought that "sleeping through the night" was a one-time accomplishment and once it happened, you didn't have to work on it anymore. But I quickly learned that it is an ongoing process, and as soon as I thought we had it figured out, their sleep schedule would be disrupted due to illness, vacation, change in schedule, etc.
Your baby is still very young, and there are so many reasons that she could be night-waking. Even though she's only nursing for a few minutes (babies become quite efficient nursers by this age), her reason for waking could still be genuine hunger. Our pediatrician, who is a cry-it-out advocate, said that some babies up to 6 months still do need to eat in the middle of the night. I've read other pediatricians who say that some babies up to 12 months still need nourishment at night. It could be that she's going through a growth spurt, which would explain why she was sleeping well before but isn't anymore.
I completely understand your exhaustion, and I would recommend in the short-term doing whatever you need to do temporarily to get more sleep so that you can think clearly about how to best solve the issue. For me, that meant bringing my baby into our room, but for others that may mean sleeping in different part of the house while your husband tends to the baby's night needs or deals with letting her cry it out. It's really whatever you're comfortable with.
Finally, I would recommend the "No Cry Sleep Solution" by Elizabeth Pantley. It has a lot of good, gentle ways to encourage babies to form healthy sleep habits. And I've found that the earlier you start, the easier and quicker it works. Good luck!