Sleepless nights.

The question I get whenever I tell my family and friends, that I either struggled to fall asleep or didn`t sleep at all is why? The dreaded question of WHY?? I mean it`s a simple question but the answer is so damned complicated. How do I tell them that, most nights, I go to bed tired at a reasonable time, I lay in bed and close my eyes. However instead of drifting off to sleep, like most people do, my mind is far more awake than before. 

My mind has a way of bringing fourth every mistake I have ever made, any regrets I have ever had, any choices that I wish had panned out differently, all these plus so much more. How am I supposed to fall asleep when my mind is showing me every scenario ranging from things that have gone wrong to things that could go wrong. 

Now I know there are people out there who know what I'm going through, simply because they are going through it themselves. but how do I explain it to those who have no idea what it`s like to deal with this. I mean at this point it is literally like that Katy Perry Quote : 

''You walk out the door, and you see someone you know, and they ask you how you are, and you just have to say you're fine when you're not really fine, but you just can't get into it, because they would never understand.'' 

I feel like I can`t talk to family or friends because they don`t go through this and they definitely would not understand what its like feeling like this. I mean how many people can actually say that they have had this happen to them so bad to the point where they actually get an anxiety attack whilst trying to fall asleep, because I can.