That is, you stretched, which means you practiced too much for the first time, so you should do it step by step. Do ten exercises a week first. When the muscles get used to it, do more, and then follow the regular plan.
Nothing, eat more meat and some anti-fatigue food. Usually pay attention to rest and do more activities. Don't be afraid of pain, don't move. It will be ready in a week or so! It's nothing.