Did anyone witness this? Any adults? Your parents? Were you ingesting booze or drugs? Do you have a history of seizures? How long did it last? Any numbness afterwards? Any history of epilepsy in your family? Did you get hit on the head earlier that day? Can you walk, speak, swallow normally? Hearing and taste normal? You've got to see a doctor - preferably a neurologist - and immediately. Don't chance it.
It is not good. You are putting yourself at risk and others too by not telling. You need to have it checked out by a doctor. It could be a symptom of something more serious. What if it was due to a tumor that wasn't yet cancerous but could be? What if you were responsible for watching a child and you became incapacitated? I'm sure it might be embarrassing but tell your parents.
First thing you have to do is discuss this with your doctor. I mean that. Make an appointment tomorrow.
Second, I have to ask, what form of seizure did you have? What do you remember about it. Was there a kind of system warning before you had your seizure (often referred to as an aura). The more you can tell me about what happened to you during this seizure, the more I can help you understand what form of seizure you are having. Note: I am not a doctor, but I have had some classes on seizures and, more importantly, I do have epilepsy, so I know what seizures are like when they happen.