Spells of dizziness, paranoia and fear.

At around 8:35 this morning I was lying down watching TV and then I heard this kind of buzzing electrical noise inside my head for a very short time (maybe a couple of seconds), I then felt very dizzy and I could not see straight, then came a period of about 3 minutes of paranoia. I thought nothing of it an continued watching TV, however at around 8:45 the same thing happened although the paranoia was much worse and I felt extremely scared. I was then in the bathroom on my own, at about 9 am and I had another of these strange spells except the paranoia was unbearable, I had to run to where a family member was and I felt as though I was safe. For about 10 minutes after this I felt very paranoid and had to check behind all the doors and things and could barely walk into a room on my own. At 9:15 I got a very mild headache, I still feel a little paranoid and have to check behind me every couple of minutes. At the moment I am in a month of exams which I have been extremely stressed for which may have added to the problem. I'm 17 and have 5 months left of school. I know this is overly detailed but I thought it may be useful. Really appreciative for any help you can give.