Help me

Ok so im on tha depo shot i love it theres no periods jus a few side affects i recently jus got back on in September. Planned parenthood told me i was due for my shot on Christmas eve and that i would be on time. So me thinkin i was on time i had sex Christmas eve && This Morning.When i called to make a apt because here in Michigan tha one i go to is only open 2 days a week and so when i called to make a apt the receptionist told me i was late & tht they dnt accept my insurence so i couldnt be seen. Is it possible now that i could be pregnant?. I got tha shot september 25th