Should I cut off my unattached toenail?

I am pretty sure I have Onycholsis. I've gone to the doctors but all they have said was a fungus. So my right big toenail has an unattached toenail above it. The new nail comes halfway up my nailbed. Do I cut the unattached toenail all the way down to that point? My doctor has never told me to do that but everything on the Internet does. I'm scared, I don't want to mess anything up, what do I do?please help.