A possibility of seizure
is highly likely. EEG done for 30-40 minutes may not be able to pick up these problems. Better to go for a overnight Video-EEG to characterize the event. This will really clarify the picture as the event will be captured and at the same time we will be able to see the problem in the brain. Please visit an Epilepsy
specialist in the local area and get the test done.
You donot have to worry.