Select last N rows following a condition

Select last N rows following a condition

I've got a database table with logs which has 3 columns:
date | status | projectId
status can be either 0 or 1, primary key is on date and projectID
I'm trying to find out how many times a projectID had status 0 since the
last time it was 1.
so if there would be only one projectId
date | status | projectId
1 0 3
2 0 3
3 1 3
4 1 3
5 0 3
6 0 3
this should return 2 (row 5 and 6 are 0 and row 4 is 1)
The thing that makes it hard for me is that I have to maintain the order
of date. What would be a good way to tackle such problems, and this one in
particular?