Possible chemical at 4+3

I got a BFP a few days ago and today woke up to period like bleeding and cramping this morning. I'm pretty sure it's a chemical, but the test I took today showed some line progression compared to the one 2 days ago. Has anyone else had this happen? Did everything turn out to be okay or did it just take a while for the tests to show negative??

I went to the doctor for my last chemical and they sent me home and said "just let it happen". I know there is nothing they can do so I don't plan to go in unless the bleeding continues and the lines continue to progress. I just want to hear others' experiences because my tests were negative almost instantly last time!