My son never had colic, thankfully, as that might have pushed me over the edge. He, however, never slept through the night until 14 or so months.

The one thing that did help was a visit with LLL, and a lactation consultant. I learned about cluster feeding, and that seemed to help some with the longer sleeps. (Like you, I didn't do the formula thing to fill him up- gets in the way of the supply issue!). And, I learned from LLL the true art of nursing while in bed- no light. That helped a lot, since I could lie down, and the light wouldn't wake anyone up more. I wonder if you can set up a mattress on the floor in the nursery, temporarily, to allow for co-sleeping? It might help.

The best news is that this IS temporary. And, when you find yourself becoming overwhelmed, remember that you are not spending the next 6 months like this...it is just 'one more night'.