Poor you, that really is tough.
With our almost 2 year-old DD, we've noticed that the more involved we are in trying to get her back to sleep after a night waking, the longer it takes.
It sounds like you need a bit of tough love for her sake as much as yours - her sleep is also suffering and it sounds like she needs to learn self-confidence in her own ability to get off to sleep without your input.
I would definitely night-wean as soon as possible, if you can face it. She won't like it because it's a change to what she currently wants and expects. But that's part of the weaning process.
In our case, DH went in to comfort DD during the night, sometimes offering water in a sippy cup. It didn't take her long to get the message.
We also stopped allowing DD into our bed. Lights stayed off and she remained in her cot until a time we deemed was acceptable for getting up (06.00).
We found with our DD the least intervention the better, so we accepted that she would protest for a while but would give up when she realised the attention she craved wasn't forthcoming. So if she wakes, we go in after a couple of minutes to check she's okay, offer a sip of water etc. then when we're satisfied she's comfortable, we tell her we love her, that it's sleep time and night night. Then we leave. This method meant up to three hours-worth of trying to get her back to sleep was cut to about 15-20 minutes, followed by long blissful nights of sleeping through.
HOWEVER I totally understand that you don't want to leave her crying, so try a gradual retreat method - sit silently on the floor with your back to her and move closer to the door each night, or sit in a chair near the cot and without saying anything, gently lie her back down every time she starts up, then move further to the door....
The main thing is that you are consistent so once you decide to stop offering night feeds, don't go back on that. Likewise if you decide to stop co-sleeping. Once they get the message that you are absolutely sticking to your guns, it all gets easier.
Good luck. It's really hard, I hope you can sort something out soon.