I have a 15' above ground pool. One side is almost 2" lower than the other. It has been like this since for years and hasn't gotten worse. However the liner is showing some strain, with wrinkles running toward the lower side and some wrinkles around the skimmer port. There are no apparent leaks but I worry that I will need a new liner soon. Should I worry that it will not last the winter? I live in the northeast, where we get freezing weather and snow.