Confused please help.

Hello ladies, I started testing 4 dpo which was 1/20 cuz I was feeling nauseous and having a very bad backpain so I started getting what it looks like to me a positive lines. So yesterday and today I started using the first response brand but all I'm getting is a negative at the same time  still showing positive line on the cheapy strip test. Please if anyone knows what could be the reason and help me understand. Starting to get very emotional. Weve had one One miscarriage back in April and one chemical pregnancy in November praying for this to be our Rainbow baby. 🙏🏻😔