How long have you had this drive?
I actually had a G-Drive that had very similar behavior, in fact almost identical to what you describe a few months ago. After 3 years of owning it, I had very strong reason to believe it was on the verge of failing imminently after repeatedly getting random ejection warnings and very sluggish drive speed. The drive became very unstable and nothing was loading.
I stopped using the drive for a few months and then ultimately took it to a data recovery place, and they were successfully able to recover everything on the drive. I should note that my drive was close to failing but had not failed yet, however it was too sluggish to use and randomly ejected, hence it did require data recovery.
If you think the drive may be close to failing, which it definitely sounds like, please stop using the drive and take it to a professional data recovery place. The more you use the drive, the higher the risk is of the drive failing. You should take it somewhere to get it checked out before it fails if there is anything important on it.
Ultimately the risk of it failing depends on how long you have had the drive. I think 3-4 years is where I would start to be concerned if you see these early warning signs.
I don't want to scare you, but I had almost the same exact experience as you with my own G-Drive a few months ago, and I wish somebody had told me all this. I ended up getting a WD Passport to replace my G-Drive. I also have to plug the company in Atlanta that recovered my drive, they are called Data Savers, and I can highly recommend them if you are in the area.