So sorry that you had to see the motorcycle accident, the death of the man and the the death of your friend's nephew. That would be enough reason to cause you to be tearful. Meditation can also bring feelings to the surface and make you tearful. You are probably going through something that will pass on its own after you have processed the emotions.
You might try a meditation on impermanence and death. The one I was taught involves thinking that:
"I could die in 1 year...11 months...10 months...." just keep counting down until you get to "one week...6 days...tomorrow...one minute...etc"
I did this for a week at a Buddhist center and left feeling very calm. It puts things into perspective. There are others on impermanence on Youtube but I don't know what they are like.
I hope you feel better soon:)