I feel your pain, in similar situation with my 4.5 month old
I was getting mildly hysterical looking at all of the advice, books, what to do, what not to do....but went on holiday last week, had to cosleep (no cot) and had a lovely time! He is firmly back in the next2me now, but I learned that by going with the flow, I was a much happier person (and mummy!)
I spent the week BFing him for naps them lying next to him reading a book (the first since he was born!)
I reason with myself that this is a short period of time that we'll never get back (he's currently lying curled up next to me in our bed).
On a practical note, I have started ignoring some of his wake ups at night if very soon after last feed- and he invariably goes back to sleep within minutes!
I've also started feeding him lying down- makes a huge difference for me at night, even though I still have to pick him up/put hi back in cot.
I certainly haven't got it "right" (ie having a baby that naps as soon as you put him down and sleeps through 
) but what is right?! What makes us happy, that's all! Screw the people that used to get me all worked up by saying their baby sleeps through. We're happy and he's healthy, and I'm still living a normal if sleep deprived life
And, of one day it becomes untenable, I will put up with a couple of difficult weeks to get things on track.
Sorry this is a total ramble, I just wanted to share the fact that once I stopped obsessing, I started enjoying life a lot more