Hi Erin...I am a single CF mom, my son is nearly 18 and my daughter is on her own. I too am living on SSDI as well as a LTD policy from my hospital, so that helps as far as income as I don't work. My lungs are very unpredictable, working would make things worse. I am also O2 dependent, and vented part time and of course, have all of the CF treatments that we must do.
So, what do I do when I get sick? I call on my friends and family. I have learned the hard way that I cannot do this alone. If you have family or friends close to you, please call them. Most of the time, they are more than happy to help out. When I get sick, I usually wind up inpatient at least for a few weeks, often longer. While away, my pets are cared for (between my mom and son, my dog and two kitties are fed, pottied, and hopefully loved) my son gets to school and the necessary bills are paid. Once I get home, I am very weak and often on IV's....so, pretty much useless in any capacity except for writing out bills and sleeping. My mom will come by and see if I need any groceries or things done in the apartment. My son also helps so it doesn't become too overwhelming for me.
You are absolutely not over reacting....it is very hard to live alone when you are sick. Are there any volunteer groups (churches sometimes have them) that will help with lawns of people with disabilities? Even if that one thing can be taken care of for you, that would make a difference in some way. I also know how hard it is to move back with your parents, I had to when I was vented 6 years ago. I really had no other choice, my husband left (he couldn't handle my illness) and I was alone, very sick (totally wheelchair dependent then as well) and a single mom. I needed my mom's help, and so I moved in with her. It was not easy, but it was necessary. I am a fiercely independent woman, to move back into my mom's was hard admittedly. I lived with her for about 4 years until my health improved to the point where I could take care of myself reasonably when I am stable. It is good that your parents are on standby just in case for you, if things get really hard, then it is good that you have that option as hard as it is..
I hope things work out for you, sending you hugs
Jenn