Faint lines not getting darker



I took my first pregnancy test on Tuesday and saw the faintest line using a true stick cheapie from amazon. We're talking super faint. On Wednesday morning I took a Cvs digital early response and got a yes+. I took another cheapie this morning and it's still really faint. According to Glow I'm right around the 4 week mark. Should I be concerned? Scared of having a chemical. Other pregnancy symptoms are there. .. I'm exhausted and have had a hormonal headache for days.

Thanks in advance!