Should I be nervous?

Very dark test was on July 4th. Lighter test is today 17th. Today I’m 8 weeks and still positive but both lines are lighter… could it just be the test? Every test has been very dark and even dye stealing until today. First ultrasound is next week. I’m still having symptoms but nausea seems to be not as bad today as it has been which with my daughter symptoms weren’t as bad passed 8 week. Just need other opinions.