Chemical?

I got 3 positive tests including a digital. Got blood test and my hcg was 15 and then dropped to 6 two days later. My doctor told me I was never pregnant because the numbers were so low. Wtf? It was clearly a chemical. She said at 4 weeks my hcg should have been over 1000. That’s not even in the normal range for 4 weeks? So annoyed.