You've probably solved your problem by now, but this exact thing did happen to me after a storm the 4th of July. We purchased our pool just this year about 6 weeks ago. I wasn't able to be present at the installation, and I did not know much at all about how the pump and filter operate, so I was actually unaware of the filter directly in front of the pump. After I vacuumed after the storm and vacuumed up a bunch of leaves, I noticed the return water going into the pool from the filter had very low pressure, and the pressure gauge was almost 0. I also noticed the [chamber] never staying full. I tried to backwash about 4 times daily!!! I finally took it apart directly in front of the [chamber] and it was all clogged with leaves and mud! I cleaned it out, put it back together and the pump started working wonderfully!!! I'll know now to check that filter in addition to my skimmer basket. For new pool owners, like us, just be sure and put a "plug" (we used the vacuum hose!) in the hole allowing the water to the pump and filter before you start taking it apart or you'll lose a lot of water out of our pool (and it will end up all over you!)! Hope this helps you or any new pool owners.