Underwent IUI Treatment on June 30th.

I underwent IUI treatment on june 30th 2020. Now it's been close to 20 days post my IUI. Usually I get my periods between 17th but this month I didn't get my period and hence I went for HCG beta test on the 17th and results reading was 2.39. I tried couple home test kit for pregnancy and those were also negative. I was taking Dupheston and folic acid tablets. However I had stopped duphaston tablets from 15th onwards as prescribed by my doctor. Now I am not sure why my periods didn't come if i am not pregnant as per the test results. I am just getting little spotting for past 2 days randomly across the day. But the spotting is so less or nothing that I don't even have to wear a menstrual pad. I am very confused and perplexed at this point. Please advise what should I do .Thanks