Advice needed regarding new jobs and a bad sickness record. Help!?

When a potential job calls your previous job for a reference, all that they are allowed to tell them is how long you worked there, and if you are eligible for rehire. I'm sure once they say no, they will explain it is because you were sick a lot. But it could be worse, you can't help being sick! And some places don't even call past employers for references. Don't give up on your job hunt, something will turn up.