The multiple white matter
abnormal foci at your age need further evaluation. Since there was an episode of nausea and vomiting also, I would not like to ignore them. The possible cause of these foci could be demyelination
. The most common diagnosis with demyelination at your age would be multtiple sclerosis
With a history of headaches
other possible rare causes like CADASIL etc also need consideration. A neurology consultation is must to settle the matter. He will put you through some more tests which will help in arriving at a correct diagnosis.