Since telogen effluvium is reversible and self-limiting, I think you should hold off on the
Propecia for 3 months and see what happens. If the
hair is falling out a lot less, then I would continue to wait for the hair to re-grow from its telogen loss. You don't really have anything to lose--male-pattern hair loss wouldn't leave you substantially balder in 3 months anyway, and you can always reconsider the use of Propecia then.
Take care.
Dr.