lines not getting darker...

I took a test 12DPO at night got a vvfl

then in the morning 13DPO (vvfl) and later that day went in the a place that does free pregnancy test that are a little better then at home test, and they got a line after 10 mins.

then I took one today 14DPO

and it doesn't look much, if any darker, then 12DPO.

my period is due tomorrow, and I've never been though the beginning of a pregnancy or had to wait for my period because with my last I got pregnant right after depo, so I never had a period.

I should have waited till after my period didnt come to test, but now I'm just stressed.

Pretty much my worry is I'll have a chemical pregnancy, and my question is,

have you went in, got a positive with a professional, and still had a chemical?