I want to count the number of columns since last non zero value.

M J16 F M A M J J A S O N D J17
7 0 0 0 0 0 28 0 0 0 0 0 0 0
3 0 0 0 0 32 24 0 0 0 24 0 0 0
0 0 0 0 0 40 0 0 56 0 24 0 32 24
7 0 0 0 0 0 48 0 0 0 0 0 0 0

M = Months Since Last Referral, 0 = no referral that month

the first column is my manual math, for instance it has 7 in Row 2 because there is no number greater than 0 since June, July-Jan(17) = 7 months
the first column is my manual math, for instance it has 3 in Row 3 because there is no number greater than 0 since October, Nov-Jan(17) = 3 months

What kind of formula can I use to determine this automatically?

Also, I will add new columns for every month, so how can I make this work going forward.

Here you go.