Does Propecia and Rogaine lose effectiveness after few years ?

[Nostradamus]

I am 50 years old. And right away my doctor started me on Propecia 1 mg daily and Rogaine foam two times a day. and in the beginning it was working to maintain my hair after initial shedding period.
Now that its been 3.5 years, these 2 measures are losing their effectiveness, it seems like. I am starting to see more hair loss last 3 months.
My question is is this normal ? for propecia and rogaine to lose effectiveness after 3-4 years ?? Also, i do have some issue with keeping my erection for long periods of time and some tiredness from propecia.

What should i do at this point?