Hi, and welcome to TSF!
Unfortunately, I think your drive is dying. If you can manage to get it recognized, I would copy all the most important data off it ASAP.
If it isn't recognized on any computer, you can trr the freezer trick to get data off it. Take the drive and put in a ziplock freezer bag and then put it in the freezer for about 6 hours. Take it out, let it sit for about a half hour and then try it on a computer. It should get you at least 10 minutes to copy important data off it.