6 days late , anyone else see something ?

So I am 6 days late , have been testing every few days since before my period was due and every time nothing more then what I thought was an indent , this is probably the darkest one have gotten so far , have been having symptoms for 2-3 weeks

I know these tests are renowned for giving false positives but it was the only ones available at the pharmacy 🙄 have also done an inverted version of the photo

Should I be concerned if HCG is only just being picked up this late (assuming I am pregnant) this would be my second and with my first I didn’t do the test til 5 days after my period and from memory the doctor couldn’t even be sure as HCG was low so maybe it’s just me...

Have also attached a photo of a test from 2 days ago (mon) in comparison to today’s (Wednesday)