hey there, you are taking on WAY too much of HER problems.....surely she can find somewhere else to stay short term. she's a full grown adult, and there are many options. YOU are only ONE option.
with your health failing, you are not in a position to host ANYONE in your home. so de-personalize this....you are not well and you simply must take care of your health first and foremost. you did not plan to get sick just to inconvenience her.
she isn't starving and homeless - she needs a place to crash for abit. it's not the end of the world. go easy on yourself kiddo.....