I went through the same thing and it coincided with me leaving XP so i got no respite - hard work!

For me, i was BFing, so i just co-slept and let DD feed whenever she woke and tried really hard to ignore how often that was. So i had no idea if she woke me twice or 8 times, if that makes sense. I know it sounds weird but that SOOOO helped me! Not "counting" wakings in the night helped stop me counting my woes the next day. I also tried to nap with her mid-morning, or at least lie down and feed her. It meant we both got to lie down for a period and have a rest. By the time she was 5 months she could find the nipple and latch on herself so as long as i kept her close she was no bother at night.

Things improved drastically when she was about 6 months, when she was able to roll and began eating some solid food. It wasn't the food itself i think, but reaching the developmental stage of needing it. That combined with the extra activity of rolling about during the day seemed to use her energy really well and she began sleeping again.

Hang in there. This too shall pass.

Bx