15 and I may be pregnant 🤕

I'm 15 & took Plan B on June 27th but didn't recieve a period in July. I already had finished my period for at least a week in June when I took Plan B. So I was okay for the month of June. But no period in July!!! I took 2 peegnancy tests last week but they BOTH came out megative. Could I be pregnant? Even though I took Plan B and the tests came out negative? I have no early symptoms or anything. Just a missed period & thick discharge