real life lady

Love that name!!!
I'm going to assume you are on the liquid oxygen. What level are you on?? I don't know if the company will let you do this but here's how I handled that problem. First whenever I am at a medical facility, I try to use their oxygen (you may need a different cannella).
If you are on liquid, find out if you can get the pressurized 02 tanks that require them to be wheeled. They aren't heavy and last anywhere from 4-8 hours depending on your use (I am on 2). Then what I do is keep one in the car at all times. This way when I am driving around, I am not using my portable tank which allows me more freedom of movement when out running errands. It also gives me a back up, should I run out because of some unforseen delay or change of plans. I literally have the tank and it's wheeled container strapped to the middle seat of my van so that I have easy access to it.
Technically I am not supposed to have both systems, but my delivery guy basically cut me a break and will deliver both since my insurance just receives a monthly bill for oxygen (a flat rate), they're not charged by the tank. At home I am on an electric converter (can't think of the name). If I have alot of errands to run that requires alot of in and out of the car (which can be exhausting) I bring one of my kids so that they can do most of the driving. Even saving steps by having someone pick you up and drop you off at the door can be a big help. And of course, walking slow goes without saying. I also have them along to load and unload the car, saving myself any lifting (which requires alot of extra oxygen)and I avoid stairs and any place that will be extremely crowded. (shopping at off hours).
If you don't mind me asking, why is it you are so short of breath? Would going on a steroid drug help you?
el