Positive then negative two days later?

[babydoll190]

So on the 15th of august I took a pregnancy test it came back with a faint positive as I had taken the test on the day my period was due, however I though I’d test again yesterday and the test came back negative!? I’m so confused I haven’t tested again, my period is now late by 4 days? Am I pregnant?
Below I have attached the faint positive tests and then the negative test,
Feel free to share your advice :)

You might be better getting a first response early result as they are more sensitive, although If your period is 4 days late it should show up on most tests by now. There is a chance you've had a chemical pregnancy which has in turn delayed your period a few days. I'd wait a few days and test again or see if you bleed. Sorry op