Advice needed ! Please help !🙏

Ok .So I had a miscarriage January 6th at 7 weeks. My hCG levels returned to normal (0) and I had a normal cycle around February 11th according to my OB. I took a opk and got TWO positives on March 5th and 6th..Then took another one a week later(March 12th) and got a positive... I was supposed to start my period on March 13th .. I am late ..but testing negative on hpt .. Please help !!! What is going on ?! Any advice ? Thank you