Endometrial thickness. I've cyst too?

I'm 21 year unmarried girl i was pregnant 4 weeks got my abortion done with like normal periods and bright red blood and pinkish blue discharge that lasted for like 7 days from heavy to light i underwent transabdominal scan becoz my test pregncy test was faint line positive and i missed my periods again which reported thin wall ovarian cyst and endometrial thickness of 10.9mm my last lmp was 24 july 2020 a due to abortion pills and i did beta serum hcg was 759mIU/ML i don't knw why hcg is getting detected still after abortion and there is endometrial thickness of 10.9mm the gynaecologist i met she told that right now nothing is visible on scan and gave me northisterone tablets for 5 days m i pregnt or the hcg is residual and thickness is due to i missed periods and I've cyst too ?? Please answer