Possibly pregnant between mirena and depo

Sasha • Wife. Stepmom. Dog mom. Student, and future Army officer.
I had my mirena taken out about 3 weeks ago, and got the depo shot the same day! The doctor told me to use a back up method for a week, at which I failed to do. I don't know the possibility of me being pregnant, and am too early for it to read on an at home test...