I've never had this symptom but I found a condition online called Transient epileptic amnesia on Wikipedia.
"During an attack, the person is usually unable to remember things that have happened over the past days or weeks. Sometimes, the memory loss may affect events from much further back in the past. In addition, the individual often finds it difficult to retain new information and may ask the same question, such as "What day is it?" or "What are we supposed to be doing today?" repetitively. There is, however, no loss of personal identity and close friends or relatives are usually recognised. The physical appearance of the person is normally unchanged. Observers may, however, notice some pallor of the skin, a brief 'loss of contact' such as not seeming to be aware of the person witnessing the attack, or some automatic movements such as swallowing, lip smacking or fidgeting of the hands. In most cases, however, the person responds appropriately to the situation they are in. They carry on conversations and can continue with activities such as getting dressed, walking or even playing a game of golf.[8]
Attacks typically last 20 to 60 minutes. Some attacks may be less than five minutes in duration. Much longer attacks have been reported; in the 2007 study of 50 TEA cases, one lasted four days and one lasted two days.[4] Such unusual presentations "may be due to ongoing seizure activity (non-convulsive status epilepticus) or persistent post-ictal dysfunction of memory related brain structures."[3]"