The flight does indeed seem to be cancelled, but there are still plenty of options with other carriers from SJC, and even more from SFO.

How did you buy your ticket (from an airline direct, or through a Travel Agent)? That will determine who you'll need to call, but when you do have your preferred plan ready and tell the agent what you want to do. Inevitability that's going to be an easier conversation if you pick a oneworld option, but BA is obligated to put you alternative carriers if needed.

If you use SFO, the airline will cover the cost of you getting there (presumably a taxi).