I have to drop a course , for which I need a very strong reason and a convincing way of writing.

I have to drop a course , for which I need a very strong reason and a convincing way of writing. If anyone could write a good letter for that , I would really apperciate it and might take some ideas from it. Some of the reasons could be - physical health(cough and cold), 5 courses ( too much workload) , etc

Subject is psyc 100 (phychology 100)

Thanks