Should I accept new job - newly auto immune?

I've been looking for a better paying job so that I can keep my house (boyfriend moved out a couple months ago - I'm struggling). Been battling hives for 6 weeks. Got allergy tested; not allergic to anything. C-Reactive Protein elevated. Decided it's probably auto immune - waiting on more results now. Had second interview last Friday; sounded like they are going to offer me the job. Pays a little better and benefits are almost $300 cheaper per month. I've missed 4 days of work in the past month. I'm thinking I shouldn't take this job - especially if I have Lupus or something that's only going to get worse. I don't want to start out a new job by calling in sick every other week and taking time off to see Dr's, etc. On the other hand, if I don't make more money, I will lose my house. I expect them to call me today or tomorrow about the job. What should I do?