This is an issue that resolved itself, but I figured I might as well create a Topic about this in case anyone else has encountered it, and as a way to share the interesting experience.

I brought my Power Armor into Corvega Assembly Plant, took a few blows and narrowly avoided a grenade blast, but no damage was done to my armor and no limb injuries were sustained. However, my health was nearing the halfway mark, so I used a Stimpak before proceeding any further. It didn't seem to do anything. I shrugged it off, then walked up to a Terminal. Couldn't access it. Got out of my armor and tried again - still couldn't get the hack screen to come up. Then I looked at my health again and noticed it was still low, so I used another Stimpak. Then I finally noticed that my health kept draining for no apparent reason. In the end, I decided to try hopping into a vacant bed, slept for one hour, and...the issue was fixed, and was able to access the Terminal as well.

I don't think there was a head injury involved, as no such injury notifications came up during the entire firefight. I believe it was just a weird glitch, and am glad it was something fixable and not permanent.

We're you poisoned somehow like from bloatflies or mylarks? That's how my health lowers with no enemies around. Wish that it did the loud poison noise and screen effect from New Vegas in this game.

Nope, I was fighting Raiders. I would think that when you open your Pip-Boy to the Status screen it would show conditions or injuries. It's just odd that I somehow wasn't allowed to access the Terminal either, but it was all fixed by jumping into a bed.

EDIT: And if it had been a head injury or something to that effect, then a Stimpak would have fixed it, but that wasn't the case.

OK I've done some research this is a very common bug in that factory a lot of people on different forums were talking about it, sleeping or going to a doctor at the only ways to fix it.

Ok, makes sense. Glad that I ended up fixing it on my own. If it ever happens again, I will know exactly what to do.