I'm confused I was just at my ob/gyn

So I was just at my ob/gyn appointment and she told me when testing for ovulation that you can actually ovulate two days before or after a positive test.? I thought it was after a positive test. Also is it normal for her to order a beta hcg test? I mean i didn't see the urine test or ask about it I'm only 9dpo so I figured it was neg. just curious.