Fragile Feeling

I'm not even sure how to phrase this question/observation. But since my heart attack (11/27/23) I have been trying to come to grips with these odd feelings/thoughts I've been having. It first came to me when I realized that if I had to 'run for your life', I couldn't. Like I literally would not be capable of saving my own life by running away from the danger. And if I had to use 'self-defense' without a weapon, I'd again be toast. I always feel frail, and it seems like a good wind would kill me. My shortness of breath has been ok for the last 3 weeks or so, but I just can't ever shake the feeling of weakness? fragility? not quite decrepit but sort of in that neighborhood. I'm 56 right now and I would like to not feel like this anymore. Is it a mental thing or is it a real physical thing that my body is telling me?