Can someone please help with the confusion?

HCG was at 53 and droppes to 42. I was only about 3-4 weeks and saw what they thought was a gestational sac on the transvaginal ultrasound... i think beta was like 8 and dropped to 4?? No bleeding or cramping still lots of CM and boob tingles.. why did my doctor say its a chemical if i still feel these things and have no bleeding ect??