Hi Rhonda, I’ve had a weekend just like yours, sorry.
External drives bought within the last two months are not found, and some older ones too, are not mounting on any computer. Tried different cords, updated NTFS for Mac software, different ports, rebooted machines, tried on three computers, Utility/Disk Repair. Western Digital, Seagate. I have backups of all but my “Master” drives keep me sane, even Dropbox isn’t showing Thumbnails for some files…frustrating for sure. It seems that after 12+ hours…it can find the drive again, wtf! I don’t have any answer for you because I’m still dealing with the workarounds!