All of a sudden I can't hit anything anymore. When I toggled on the combat statistics it showed me that the chance of me hitting some creature or NPC was actually negative, something like -40%. How is this even possible? I don't use any mod that tweaks any settings.

-how do i check for a tohit chance?
-maybe your agility is drained and he has high defence.

You can toggle the combat statistics in the console with the command toggle combat statistics and its abbreviation tcs, never knew about it until it became impossible to hit and I had to check out what was going on. My agility is normal and it was just a blighted rat I just went looking for the problem again and now it was all of a sudden possible to hit others, but only with a chance of at most 20%. Maybe it does have something to do with a mod, but I don't have a clue which.

thanks. 20% doesnt sound so bad actually. 1 out of 5. Fighting rats, ive seen worse, far worse. Then again my fighting skills werent spectacular. There was a tohit formula floating around. I think it was 1.25weapon skill + agility/5 + luck/10 - attackers def. but dont take my word for it.