Please help!

Ok so by my calculations with ovulation, I should be 4weeks 6days pregnant. Yesterday and today I have had brown spotting no cramp or anything. Today I took these tests. This is the darkest line on the Walmart cheapie that I've got so far but why would the frer be so so so  light??? I'm so confused and starting to worry! Please let me know if any of you have been thru this! Thanks! Baby dust✨✨✨