I winterized my pool and let water go out both the skimmer and the water inlet so it was fairly low. I put the cover on and now there's maybe 1 ft of water in the pool. I'm assuming there must be a leak somewhere in the liner. I'm concerned with that little water that the walls might collapse. Any thoughts? I could try adding water but there's no reason why it have gone down that low so it must be leaking but it wasn't all summer. I'm baffled!