Help me plzz 😞

Guys plz help me i’m so stressed right now. Me and bf did sex last month (we used protection) i got my periods on my due date but my flow was so light and after I stopped bleeding i got my blood test done (beta hcg) which came negative. Now its my sec month i’m 4 days late. I’m so worried. Can i be pregnant 😩 ? plz help me guys.