Got fixed. I suppose.

A witch spawned in my base so I went to kill her, only she won't die. She's killed me once already and I've broken a stone sword on her. Not to mention I've hit her several times with an iron sword as well and have nearly broken it too. I can't play in this world if there's an invincible witch in my house D:

EDIT: Okay so I killed her, but I see the problem. She's drinking Health Potions almost constantly. I had to spawn in a Diamond Sword to deal enough damage to her and kill her, but I could see she was constantly drinking health potions. She drank like 6 in a matter of seconds.