Talk to Gynecologist on Miscarriage

A.o.A My LMP was in 15 june and I was 7 weeks pregnant when I became to know that my sac was not seen on ultrasound and start bleeding after ultrasound.My Dr said that u may be in situation of biochemical pregnancy but a small sac piece was discharged out with severe cramps during bleeding . This month I become pregnant again and after 2 days missed period , I had a spotting but after a week of spotting bleeding starts and a small piece was discharged out again... What is this condition called?? Is this a miscarriage or sign of biochemical pregnancy