I am so confused help?

I’ve taken 7 different brand of pregnancy tests four-five weeks ago. All were positive. I have endometriosis and have had miscarriages. I called my doctor and made an appointment. Going off how far along I should be around 8-9 weeks. Blood work came back negative. And ultrasound didn’t show a baby. I don’t understand. My doctor told me that IF I was pregnant. I would miscarry. Basically sent me on my way. I do want a second opinion but I am just confused.

If I am going to miscarry, shouldn’t I have already started doing so?

Any advice would be nice. Thank you.