trying to get stronger at home after getting sick

Before I got sick, I was going to the gym regularly and really enjoyed working out. Now I cant go outside and I am having trouble walking, so I am trying to figure out how to stay active from home.I am hoping to slowly work on my upper body strength and also do some gentle exercises for my feet and legs. I dont want to push myself too hard, especially since I am starting from a much different place than I was before.For anyone who has had to rebuild their strength at home, what simple exercises helped you get started?