I have this constant fear of my toenail getting ripped off.?

i have this constant feeling that my toenail is going to get ripped off or broken or something. its the little toe in my left foot so I'm constantly touching it for reassurance.I'm worried when i walk or drive and its beginning to get obsessive.its been going on for a couple of weeks and started suddenly.Is there any way to make it stop?And any idea why it came up in the first place?