No heartbeat and I am supossed to be 6 weeks

Lea • I had two miscarriages of twins, I have PCOS and a Thyroid problem 😔
I had an appointment today at the doctor to find out if I am pregnant or not, and I am but there is no heartbeat I am supposed to be six weeks as my last menstruation, the doctor told me it could be that I have less weeks. Has anyone experienced the same thing pleas let me know