B.R.
You are not alone! I've heard many moms talk about similar problems and have had some of the same questions myself. From what I've read, 6 mo. is usually when babies can sleep comfortably thought the night (at least 6 hours) without feeding. You may want to start adjusting your baby's routine a bit, to make sure he's getting his calories during the day (starting solids can help). But also, if you are in an unusual environment, give yourself and baby a little slack. If his routine isn't perfect right now, it won't be too late to adjust it later when things normalize.
I highly recommend Ferber's book, "Solve You Child's Sleep Problems". It's very informative about the science of sleep, age appropriate sleep patterns and problem solving. It gives examples of how other parents have dealt with sleep issues. It also has a section on co-sleeping. He does recommend crying it out but progressively. The first time you do it, you let them cry only for 3 min., reassure them, than wait another 5 min., ect. You work up to longer and longer intervals. He explains why crying it out helps children learn the skill of falling asleep on their own and why babies might feel hungry in the night even when they should be able to sleep through without feeding. Even if you don't feel comfortable letting him cry it out yet (or ever--which many moms don't and there's nothing wrong with that), I think it's a useful book.
My son was still waking up in the middle of the night at 6 mo. and I didn't know how to get him to sleep without nursing him. I finally got exhausted enough to give crying it out a try. It was hard the first night (I cried while he cried!) but was easier the second (I think he was asleep before 15 minutes was up) and after a few days he was already learning to settle himself at bedtime and sleep through. Sometimes his routine has gotten out of wack because of illness or teething and then I've made exceptions like let him nurse for comfort or come to bed with me. I just reapply the method when I think he's feeling OK again and he relearns how to settle himself back to sleep.
Good luck!