Sorry for your lack of sleep, been there, done that!
My kiddo co-sleeps and has since birth, he's 26 months now. He has gone through some horrible bouts of no sleep at night and anything from 3 naps to no naps. Take a deep breath and remember that the whole sleep through the night thing, is relative to each individual child and that it will always flucuate throughout their growth. Teething, allergies, stress, growth spurts, changes in eating, weaning, all these things affect sleep and you just have to really tune in to what's going on. Adjust as much as you can for him, if he doesn't seem to want to sleep at night, try going to bed earlier or later. If you're home and can, try napping with him to get him to sleep longer (I know I'll have some nay-sayers on this, but sleep is good for everyone!) It does get better and easier and you'll both get through it!