Chemical

Would it be considered a chemical if you received faint positive then start bleeding? But what I don’t understand is why does your test still get darker? I have been through this over this last year 3 times now I have found out I’m

Pregnant start spotting and then bleeding and my blood draw my numbers continue to go up then will fall down all after I’ve been spotting bleeding?! Just confused if your bleeding shouldn’t your test urine and blood test start immediately going negative? Currently going through this again. Just haven’t gone to go get blood work this time.