I don't think you're any less irrational or worrysome with any pregnancies! I don't think it disappears. Although I know I worried less with my first, I reckon you simply become more of a worrier with each pregnancy.
To me your lines look fabulous. And in terms of progression as well as strength. Remember different tests will have different line strengths and dye in the same tests will vary also, as will the strength of your pee on top of depending on what time of day you test and if it's consistent. So many factors play into how dark those lines are, and 99.9% of the time it hasn't anything to do with the progression of the pregnancy itself, but the type of test, how much dye is in the test, strength of pee, whether you went shortly beforehand, how much you drank and the time of day. Don't worry, or try to be more calm I know it's hard, but they look fine to me, more than fine