A couple things:
Is this a self powered or bus powered drive, i.e. does it use an external power supply or not?
Have you tried plugging the drive into another computer?
Have you tried a different cable?
FWIW, when I have seen such behavior in an external drive it usually means that the drive is failing or has failed. In some cases it is the drive itself or more often it is the electronics that control the drive.
Just because the drive is "just months old" does not mean that it cannot fail, it happens. If you look at user reviews on any retail website for any external drive, HDD or SSD, you will always see a few one star comments that the drive failed within months of use. While generally not common, drives can die at a young age.