Does it ever stop???

Does the worrying EVER stop?? My husband and I were so worried we couldn't get pregnant. Month after month I was more and more convinced that something was wrong. But then Sunday I got my BFP! But then I was worried about the faintness of the lines. So I keep testing and testing. Now I have a blood test scheduled for Thrusday and I'm freaking out that my levels are going to be low cause my lines aren't super dark but I can tell they are getting slightly darker. This is my second pregnancy and I'm only 3 weeks and 5 days and I'm already driving myself nuts!!!