hmm, sounds like SA to me or SA as a result of discomfort. I guess it might be something you have to ride out for now, not much help I know but SA comes and goes and the only way I have found is to roll with it, extra cuddles etc.
If it were me i would def eliminate foods you think might be a problem and see. You could also try some meds (not at the same time or you won't know which has worked iykwim) to rule out pain from teeth/ears etc.