My pool had not been backfilled yet and there was 16 inches of water in it to hold down liner. We had a bad rain and water got behind the liner. I had to pump the outsides of the pool out b4 they backfilled and the water eventually came to a stop/ trickle. Now they backfilled and pool is full, i have alot of water on sides of pool. Theres got to b a leak somewhere. Again, there was 16 inches of water to start and no leaks. After the bad rain, water behind liner and now problems. What could this be?