Sorry to hear that you're finding things tough with Coco's sleeping Meg...
It also sounds to me like it is another one of those developmental stages.

What we did with Aidyn was very similar to Mel, we just went with the flow, and cuddled/rocked/ or co-slept with him. I never found it to create any ongoing problems, and if anything I think it was beneficial for him to have the reassurance and comfort from us when he needed it.
We've had many stages (even until recently) where Aidyn has stopped sleeping through - due to sickness, and developmental stages etc, but I know with patience and just perseverance with doing what I have always done (cuddled him to sleep etc) that his routine will eventually get back to normal... and it has always worked like that for us.
But I can truly sympathise that in the meantime it is very hard to cope with sleep deprivation... I wish I had an answer, but TBH I dont think there is any set answer, as it seems to be something that all babies go through... as much as every few months even?...