positive tests and risk of chemicals

I have a question ladies:  the day AF was due I got a positive result and the day after Clearblue indicated 2-3 weeks pregnant, which is in line with what I expect. In the last 5 months I went through 2 chemicals, my lines were super faint and 5-6 days after AF was due I started bleeding. Do you think there is risk of chemical when the line is very dark? Thanks in advance!!!