Sleepless and stressful nights

Each and every person has different thoughts when they don't able to sleep at night. Likewise I also have different thoughts. Mostly it happens with me every second or third day that I don't able to sleep. And I don't like this at all. When I wake up at night I always think about the things which was happened today. I tell you about an incident in which I don't able to sleep that whole night. Actually my friends done a prank call to me and suddenly a boy's voice came ,first I thought that he was someone from my class but by his name I came to know that I don't know him. But he know my name so I asked him patiently that who are you....and then I cut the phone. I was thinking continuously that how he got my number etc. Actually I usually stay away from all these things. And that whole night I was continuously thinking about that. Next day my friend told me that she had pranked me with some friends. I didn't talk to her whole day. So it is just a simple thing but I usually come in stress with small and little things which disturb me in night. I know that it is not right in today's world , I am trying to overcome this problem. But you all know that human needs time to adapt new things or to change the behaviour. Apart from this there are some more thoughts which came to my mind at night - as this is the last year of my school, from next year my new journey is going to start. So whenever I wake up at night I thought how my college is going to be, whether I will get new friends or not, how much percentage I'll get etc. So in different situation different types of thoughts came to our mind. Mostly I don't like to wake up at night. But it is natural. So some thoughts are good and some are bad.