Are you sure you weren't bitten, and contracted the disease, a long time ago, so no matter what you're going to become a vampire. Only way out of it now, is to do the vampire cure quest, download the DLC with the alter to cure it, or never, ever level again. What level are you? By not leveling, you probably won't miss out on too much, but then again, you won't improve either, which means creatures and loot won't improve either.
And as Guild Master you do get the chest, and place to sleep, but do not store anything in it that you have fear of losing. You do not actually own the place, so you will lose stuff. Same goes for any of the other guilds. To safely store anything, you need to buy a house. Period.