Walking is probably the best and easiest exercise to build stamina. The key is to start slow, where you are, and build from there. The first goal should be to do 30 minutes without stopping. Most of us can't do that from the get-go, so we start where we are, with the first step doing five minutes without stopping. Do that until it's comfortable and add more time; enough so that you push yourself and have to huff and puff a bit when you start, but it gets comfortable so you add more time. Keep doing that until you can do 30 minutes without stopping. I say "do it until it feels comfortable" and that should be a bit relative, in that you you need to find the sweet spot where you're sob, but not so much you can't keep going. If you're not a bit sob, you're not working hard enough to make a difference, but if you're gasping for air and think you're going to die in the next minute, you're going too hard. In addition to walking, which is aerobic exercise, you should be doing strength/resistance training with weights, bands or elastic ropes concentrating on upper, lower and core muscle groups. Weight training should be done every other day to give the muscles time to heal.

I also live in the country and live alone, so it’s very hard for me to get out and walk.

Having anxiety is one of the most crippling things. Have you asked about pulmonary rehabilitation?

Find someone to walk with you. Let them be motivator.
I live in the and hard for me especially bey self.

Thank you!