Mentally ill or paranoia ?

Well I was doig some work Which was very boring and some lad aat next to me and I was measuring something on the computer and I was on 21mm and he spoke to me, and now I keep thinking that I'm gonna swap souls with him when I get too that age. I will seem crazy to alot of you when you read this and I don't blame you for thinking this haha, but I have random thoughts like this now and again and this one has stayed on my mind and now I keep thinking that this wi happen I keep thinking to mysel is they any point in doing this like things in general because this is on my mind, I don't want anything to happen and deep down I know nothing will happen but it's like just the thought of it happening scares me