Uh, you just proved my point. You are not taking it regularly -- you literally just said you aren't taking it every day. You need to take it every day to stop the shedding.
You also said this in your original post:
Take 1mg every day, not in two month cycles. Every time you stop and restart...
You have to take the finasteride regularly. Taking it on and off is going to **** with your growth cycles and you'll never give yourself enough time to overcome shedding.