Sorry to hear your dramas with the phone.
I have mine now over a month.
I use a flip leather case now, but had none for the first two weeks and I use my phone a lot but with no screen protector and I don't have any scratches on it.
You must have hit something with sharp edges hard.
I had a SG2, never had a screen protector and was exposed as I didn't use a flip case. It never got any major scrathes, but hundreds of tiny ones that could be scene in the right light only.
This is a much better glass in my opinion.
Hope you are able to fix yours without too much trouble.
HTC M8 - GOLD DEV EDITION - Revolution HD v10.2
FW: 2.22.401.4 - S-OFF