Lately I've been bouncing up and down like a yo-yo: one day clean, then a fall, two days clean, then a fall. It is very discouraging. I really don't believe now that I will ever get to 90 days.
On the other hand, even if chas v'shalom that is true, every clean day is a gain. Those days don't disappear when I fall the next day. So even though getting to the 90 days, and eventually becoming free completely, is very important, there is no reason to give up hope. There is no such thing as "not worthwhile." Every effort I and you make is saved "up there".

Chin up!

yes, that is true, but what is it that you are doin' to get to that goal of yours?
as a matter of fact, what will you be doin' today?
what have you done?
has there been anythin' in the past that has worked?

b'hatzlachah