Chemical? Has anyone had this but still been pregnant?

Li

2 days ago I got a faint positive on 2 pregnancy tests, yesterday was still faint and also had a blood test. This morning I did another test and it had gotten a lot darker but the doctor just called and said my hcg levels are only 24 and will need to get another blood test done tomorrow as they are to low...worried this is a chemical

First 2 tests

Yesterday is top bottom is day before

This morning