What do i do about this?

for the past three-four weeks i have found everything hysterical and i do not know why. it is disrupting my life. i can't focus at work i can't remember things people tell me, hell i cant even get an because im too busy laughin at somehing. and just last week my wife's father ped away and when she told me i just started cracking up..i couldn't help it. i dont know how to stop this. what do ido???