Pregnancy test confusion

I took a test Friday at 4pm and got a faint positive. Took another Saturday at 5am and got a stronger line. I took another test just now at 4am on Sunday and was expecting to see a fairly stronger line but it’s lighter than yesterday’s... but darker than Fridays. I don’t know what to think :( Is this normal? Could it still be a healthy pregnancy? Today I should be around 9-11 DPO