So, I've been playing Fallout 3 for the PC for quite a while now but haven't had this problem until recently. Dogmeat's health will not go back up. I've tried Stimpaks, sleeping, waiting, and letting him kill an enemy by himself but it's not going up. His health is so low that one hit on him even from a Mole Rat will kill him, he also won't go essential using the console commands. He just dies everytime, so he's just sitting at Vault 101 while I do everything. Any suggestions?

Yeah, mods. Tones of them! Search Dogmeat at http://www.fallout3nexus.com/downloads/search.php and have a looky look