Faint positive pregnancy test but only when light shined behind it? (NOT the plastic)

For reference I am 12 DPO (confirmed ovulation with test and tracking)

My period is due in 2 days. But I can’t shake this feeling that I am pregnant this time. 12 DPO is still so early but I was just so convinced and curious.

The test when NOT held up to the light Is just white where the “T” or test line is. Completely blank to my eyes..However, immediately after (full exam mode) I noticed there is in fact a faint positive line… but only noticeable when I shine a flashlight through the back or it, or on the side of it. This line popped up 2 min after I took the test. I’ve done this before where I shine a light and see nothing, and have still seen nothing. It is NOT the plastic. I can tell the difference between the shadow lines on the back of the test, from a dye line. Please share your opinions.

I am obviously going to retest in a couple days but just want to know what we are thinking here.