Can sex kickstart a ‘period’ when on the pill?

I’ve heard that sex can cause your period to starte early, but I always assumed it would be when on no birth control.

I’ve been on birth control for many years now. I usually do take them back to back but I’m 26 days in now. I had sex a week ago after which I spotted including the day after. Masturbated today and yesterday and spotted straight after it too.

I’m wondering if this is just my bleeding kicking in or something else.

(I’ve also been to docs about bleedings before as I would sometimes occasionally spot and been tested for all STDs, I’ve had a few UTIs in the past but this doesn’t feel like it)