infants and sleep are never a constant. it changes from daily to periodically.. likely this pattern wont stay forever either.
you dont sleep train anyone. you nurture. you love. you respond. babies dont have the tools to "learn" from desertion.
she might be scared in her own room. she might miss you. she might have some teething pain. she might just be gassy. she might be on the verge of a growth spurt or developmental milestone. if shes nursing frequently, it sounds like a growth spurt is coming on. nursing frequently, day AND night, is the best idea. i know you are tired, i know you dont want to sleep in the guest room, but it will help your milk supply increase properly, and it will help your daughter grow in size and confidence that you are there for her when she needs something. and to an infant under 1 year, everything is a need. they dont know how to manipulate you yet! shes not doing it on purpose, she doesnt realize that its disturbing your sleep.
i think you are doing the right thing. my son self weaned at 20 months, and he nursed at least once at night until he was between 15-17 months. he slept with us, or with me if he made it until my husband went to work, long after that (still does sometimes!) his crib was in our room until he was almost 3.
and theres nothing wrong with this!! he is an AWESOME sleeper, always has been (except he did this too, he would nurse sometimes all night long! and it IS exhausting!) but he is a confident, excellent sleeper because i never felt the need to leave him alone and deserted in his crib in another room. i felt the need to fulfill his needs, whenever and whatever they were. and it worked like a charm!
i can put it this way: if "the world" tells you to ignore him, let him cry, "train" him, etc etc etc, and the majority of kids in "the world" are a bit messed up, than obviously the system isnt working!!! its simply deduction and logic. if a majority of parents do X and a majority of kids turn out Y, then X causes Y.
just KEEP DOING WHAT YOU ARE DOING. i promise you, you are getting more sleep than parents who ignore their babies, and its better sleep because you are constantly reaffirming your instincts with your child, instead of feeling guilty, sad, aweful, torn, and heartbroken. after a while, parents start feeling as if they are "fine" and it "doesnt effect them anymore" when their babies cry. think about that for a minute. it doesnt effect them to hear their babies cry!!! does that not just sound like the most aweful thing you could say about your child?
just use your instincts. you are being a fantastic mom. im sure your husband (boyfriend, what have you) misses you, or wants you in bed with him, discuss having baby there too (with extreme caution and sensibility - no heavy blankets, caution with pillows, etc. even separate blankets can help). OR simply making sure that his needs in your relationship are fulfilled by having private time at LEAST 1-2 times a week (this was VERY important to my husband, and we totally made it work!). then the only thing you have to worry about is the opinion of people outside your home, and they shouldnt matter one bit. you take care of your family. :) do what YOU feel is best. dont do what anyone else says. this is YOUR child! only you have been specifically given instincts for your specific child. only you know what to do! :) follow your heart, your instincts, and never give up on that! trust me, when your kid is 2, and you can instinctivly tell that shes throwing a fit because shes _____, you will thank yourself for listening to all her needs all along. :) instinct grows only by listening to it and following it.
anyway, keep it up like i said. :) she will flop into a new routine shortly, and it will be something else thats keeping her up. ;) when they learn something new, like turning over, crawling, standing up, etc, they always have sleep interruptions.
if you think its teething, try some of that hylands teething stuff. its awesome! :) mylecon drops for the tummy ache. :)