I almost got into an accident and it's been on my mind all day...

[Angrboda]

When there's danger involved, signaled by a rush of adrenaline, your brain marks those events for special processing. It's a way of making sure that you learn important lessons. As a result, it will be very current and distressing in your mind for a seemingly long time. However it will fade with time. Stress may cause you to remember this time, such as other near accidents, but those times will fade rather fast. Just give it time and you'll get over it. It may be distressing until you do, but that's kind of the point.