Going to sleep wearing your contact lenses can be dangerous, but in most cases, you will simply wake up with your eyes feeling a little sore and tired. This usually passes over the course of the day, and you should be fine by the next day. However, it is usually a good idea not to wear your lenses for at least a day after you have slept with them, in order to give your eyes a break. If you have been wearing your lenses over the last three days, perhaps your eyes are just not getting enough of a chance to recover from the contact lenses. If you have a pair of glasses on hand, you should use them for the next two days and see if there is any improvement. If you don't have a pair, either try to manage without your lenses or wear them as little as possible, putting them on only just before you leave the house, and taking them off as soon as you return.
If there is no sign of improvement within 36 hours, you should visit a ophthalmologist, as you could have an eye infection. Sleeping with contact lenses impairs the flow of tears to the cornea, increasing the risk of eye infections, some of which can be very serious.
answered by M W