I have irregular periods (the last time I had my period was over a year ago)but after having sex a week later I was spotting, does that mean I'm pregnant?

Sorry, but you'll have to be more specific. Why did you not experience your period for the past year- birth control?

Yes, it is possible you could be pregnant, because of the sex but I can't say how possible without knowing if you used protection/contraceptives, or even when the date of your last period was/ why you haven't had it in so long.