I have a 20 month old daughter who still nurses. Right now it isn't annoying me, but there have definitely been those times. My daughter was big, too, in her first year, and for quite a lot of that first year, it felt like there were days when all we did was nurse. It can make you feel pretty crazy.
Things that helped for me: one issue is that it can be boring and frustrating to nurse for long times in the day. I felt better when I had a lot of books to read while nursing, or got the computer and did email while she did her thing. Also, you don't need to stay in the house all day just because you're nursing. Take her out in a sling or babybjorn, you can even nurse her in the sling. Or push her round in a stroller, I found my daughter chilled out with motion even when she wasn't nursing, and it helped me get exercise.
The sleeping thing is the worst. I think you should experiment with alternative ways of helping her to sleep, OTHER than crying it out. Right now I stroke my daughter's back in her crib until she falls asleep. No nursing to sleep, but also no abandonment. We had a hard time figuring out a way to get her to sleep without always the breast, but it's worth working on, I think. It's also worth knowing that you can sleep-wean or night-wean, but NOT wean entirely.