I've had the same experience. I stopped exercising a year later. Later, when I was exercising again, I found that my physical strength was not as good as before, so I wanted to recover and I could do less push-ups every day. I insist on doing 20 push-ups every day, and I can do 30 at a time after a week, so when you persist for a week, you will find that your physical fitness seems to be getting better again.