If you can sleep uninterrupted for 12-14 hours frequently, you could have a thyroid issue.
Sometimes on our busy days we feel as if when the weekend hits, we're going to sleep the entire two days away; however, normally this is not anywhere near possible. We might be able to get a few extra hours in, maybe even ten or eleven if we are really tired, but most of us will naturally wake up when we get in that 12-14 range. If you are regularly able to sleep this long, it is likely a sign of something more serious occurring, often a thyroid problem.
Hypothyroidism is when your thyroid does not perform at full capacity, and it can drain you of your energy. As a result, if you have the condition, you may find yourself sleeping for very long periods of time without a problem. Fortunately, symptoms can be eased by changing certain aspects of your lifestyle, which will lead to more energy and regular sleep patterns.