Can you wake up one day with epilepsy?

Yes: Epilepsy can occur literally "out of the blue", and may be difficult to relate to any past events. Some get risk when lack of sleep, stress, poor diet, use of alcohol, illegal drugs. Maybe a long forgotten head injury, a prior viral meningitis which was too mild to pickup, a problem as a baby or toddler. Get a full evaluation from an epileptologist, as maybe there is a clue somewhere.

Let me explain: About 2 in 100 people in the United States will experience an unprovoked seizure once in life. However, a solitary seizure doesn't mean you have epilepsy. At least two unprovoked seizures are generally required for an epilepsy diagnosis. Good luck.