Help me.. chemical pregnancy

Hi ladies I got faint positive lines at 9 dpo through 12 dpo and bled before exact day my period was due. So I think I had a chemical pregnancy . I have some questions regarding chemical .I have normal 28 to 30 days cycle..

Can someone please tell me your experience of how long do after a chemical ovulation happens?

How long does HCG stays in our system after chemical?

Thanks in advance