What are the chances of pregnancy with irregular periods after stopping the pill at 50?

Hello, this is the context for my question: I stopped taking the pill two months after turning 50, I’ve had irregular periods every month since then, several of less than 28 days. I’ve been 6 months now without the pill, using coitus interruptus. This month, I should have had my period 6 days ago, and I have no symptoms whatsoever, for a coming period or for menopause. What are the actual chances of being pregnant? I’ll visit my gynecologist in one week, but I’d like to know in the meantime how doctors treat cases like mine.