I happened to check my YouTube history and noticed that it has several videos that I definitely did not watch. I have logged in to my email on this youtube on my phone and laptop only. I’m 100% sure I did not watch those videos. It’s weird. Is this just a YouTube History glitch or should I be wary of my account getting accessed elsewhere? 
If you’re hacked, you might not be able to access your account anymore. I guess, someone just used your device and watched some stuff? But if it’s not the case, just change your password and see if that happens again.
Do you have YouTube logged in on any desktop/laptop browsers?
Maybe there are videos popping up as ads when you’re scrolling on social media or surfing the net, and those videos on youtube are maybe added to your history.
Maybe this is the cause. I’ve been watching Kdramas on a free streaming platform with ridiculous popping ads which redirects me to other sites or other apps, and yes, sometimes videos, which I exit right away. But maybe this has something to do with the weird videos in my history.