Missed period BFN

Miranda

I had endometriosis surgery in January, found I had stage 3. My period came last month and was super heavy and last 8 days. Expected sense I just had the doctor doing a DNC and taking the spots out. Also have fluid passed through to check for swelling or blockages.

Anyway! I was supposed to have my period 3 days ago. Nothing. Took a pregnancy test, negative. Can anyone tell me if this is normal after the surgery?