The digital clear Blue read not pregnant
Not all test are created equal. In some test like the ept early response they detect less pregnancy horomone in your urine and some like the cheap dollar store ones you must have much more pregnancy hormone in your urine. Wait a couple of days and test again.
You likely had an evap line on your first test. That's why they say to discard a pregnancy test after so many minutes because an evap line can appear and look positive when it's not. The digitals are a lot more accurate, and if it's saying "not pregnant" then you're likely either too early to test or not pregnant at all.
Honestly all test are fine to use, both of my pregnancies i took all kinds of tests, from cheap ones to expensive ones, I used both of the ones you're talking about. Wait a few more days to a week to take another one, any brand.
The only way to really know is go to doctor so they can tell u for sure.
I don't necessarily think its fully the tests fault. I tested positive a week before my period on a Walmart 88¢ one. When my blood tests were done my hcg levels were surprisingly high. It depends on your hcg levels when you test. Some women won't test positive for a week or two after their missed period on store bought tests. Or you just might not be pregnant.