I would assume a leak, also--and usually when the pool starts leaking, the water level will stabilize at the level of the leak. Do you see any obvious rips, tears, holes, around the existing water levels? Any places around the pool that have stayed wetter than usual?If you think the liner can be saved, you can try to fill it a little and then see if the leaking stops at the same level where it is now, but I honestly think that's just going to be a waste of water.

If the liner is wrinkling and pulling away, I would think that the answer is going to be a new liner, although there are some others around the forum that can tell you if it can be saved (Waste??? Ben???). The good news is that this time of year some of the liner companies are discounting last year's models to get ready for the new year liners, so maybe you can get a good deal on a new one.

I'm sorry the year is starting this way!!