Suggest Remedy For Problem In Pregnancy

Hello, I am pregnant with my second child and I have PCOS and am still nursing. Docs told me it wasn t likely but here I am! My son came at 25 weeks so I rushed to the doc for an early u/s, not sure how far along I was. (had taken a hpt 2 weeks before and it was negative) They determined I must be very early since all they saw was a thickened uterine lining but no sac. I had an consult with a mfm the following week and they told me to keep it for their scan. One week later, i had a gest sac that was dating me at 5 weeks 4 days and the start of the yolk sac. I go back in 2 weeks for a scan to make sure there is a heart beat. My sister just miscarried and it s all I can think about. I m 27, 5 6 and around 160 lbs. Should I worry?