It's definitely a mod as I had the same problem. I'm new to this so I don't know what a lot of those mods do but I'll outline my situation in the hope that it will help you narrow down your issue. I installed Project Nevada halfway through my current character and loaded a save I made just before a fight. As soon as I got in that fight I died, reloaded, won the fight but only had like 10 HP left. Turns out it was part of PN's rebalance settings. I went into MCM and changed all the rebalance settings to their vanilla values and the problem is solved. From what I can see you don't have MCM installed. I don't know how many (if any at all) of those mods work with MCM but you should install it (link: http://newvegas.nexusmods.com/mods/42507). Then, when in game press ESC (pause menu) and you'll see a new choice at the top for MCM. Go through the menu on the left and see if any of the mods (if they're supported) are changing how the game plays, if they are then change the values to match vanilla settings. Hope this helps!