pregnant or late from plan b?

I had a period June 16-20 which is a little short for me, usually I have a week long period. I had unprotected sex the 21st and got a plan b the next day. I thought maybe I bled the 27th-29th due to the plan b. Now my expected period is a week late, could I be pregnant? 😣 Im getting a test later today but just wanted to know if anyone has had a late period like this due to a plan b?