Melissa, I don't know if your issue is resolved or not. I've had the same issue for about a year now. In a typical day I get about two notifications. I watch about 60 threads. Due to the apparent lack of activity I've seriously considered stopping visiting this site. Yesterday I went to my watched tab and went into every thread that was highlighted as having new posts. That solved the issue. In less than 24 hours I've had close to 20 new post notifications. Clearing up any backlog might work for you too.
Ps: I still can't respond from my old iPad so I am using a different tablet to post this so any lack of response from me could be hardware related on my end.
Rod