Six months is also a time for a huge growth spurt. If she's gassy, that only adds to the problem, my dd was like that. You can try homeopathic remedies for both teething and gas.
to nurse every couple of hours, and yes, it is very difficult to see through these times as just a phase, but I've done it four times, and you can get through it too. What helped a lot was taking naps during the day, I became very lazy about my housework, and dh doesn't care so much anyway. Things of priority got done, but not general straightening, kwim? You cannot make a baby fit your schedule, you have to figure out a way to adjust yours. That sounds harsh, and I don't mean to be, I'm just sharing what I have learned raising four kids. Trust me, I have had only a handful of nights when I slept more than 5 hrs straight in 10 years, so it can be done without losing your mind (well, not completely anyway
) It is hard at the beginning to doze back off after waking to nurse, but you can learn to, out of necessity if nothing else. Your sleep patterns will change, and your body will figure out how to make do with those short spurts when you can sleep.
Other things you can try...
...rubbing her belly after nursing to help the stomach and intestines do their jobs
...take a couple of days off to do nothing but nurse all day, hang out in bed and just play, etc... hopefully this will help her eat more during the day and then she won't need as much at night.
...don't introduce any new foods for a while, let her body get accustomed to the ones you have already introduced
take care of yourself, mama