i had that same sort of problem with my almost 9mo a couple of weeks ago... turned out he had a double ear infection, have you tried pain meds & a trip to the Dr. Often they are ok during the day it is only at night after they have been lying down for a while that their ears start to get sore & so they can't sleep, but because it is high "separataion anxiety" age, they want you there.
just a thought