Your writing can be difficult to understand, I hope that is simply due to lack of focus/attention to detail when posting here.
Does your transcript show mid-term grades, or are you saying the midterm grades were so bad they resulted in poor grades for the marking period?
It is ok for you to mention in the additional info section that you had covid and were hospitalized for pneumonia in first semester junior year. This put you behind in classes and negatively affected your grades. But you were able to catch up and do well second semester.
That’s it, no longer than that. No mention of asthma. No mention of swimming. No mention of missing school for swimming.
I also would strongly prefer your counselor write something like this (if you need a counselor LoR for any of your schools). To help that person, show them what you have written.