Bad dream please please help!!!!

I had a horrible bad dream last night that my boyfriend, a friend of ours, his sister, and some two year old that was for some reason apart of our family  and I were in a car that skidded off a bridge and into a lake... we were submerged for a little while but I could kick out the window and I managed to swim to the surface. I thought he was right behind me but he was missing. I said we need to go back for him and the two year old but no one responded. His sister eventually said, "they drowned." 
To make matters worse, in the dream we had been on the way home from the hospital because he had injured his arm...
It was so vivid I woke up panicked, and all day I have felt very sad and nervous. I don't even know any two year olds! I even cried a couple of times. I've talked to my boyfriend and I know he is alive and well, but I am terrified that something bad will happen to him and don't even want to get in a car at all! 
I can't sleep now either... I've looked at other posts on here but they all seem to be about pregnant women, and I'm not pregnant. Has anyone experienced anything like this? Any help to calm down?