Chemical miscarriage

I took a pregnancy test and it was very faint positive . But 3 days later started bleeding like my period . Went to ER they did  not see any sac or anything. My pregnancy level was 2 so I had lost the baby. I just was wondering I keep thinking I could still be pregnant . but took anther test a few days ago and it was negative. I was wondering if anyone has got pregnant right away after a chemical pregnancy ?