Test line getting lighter..

Ok, so I'm gonna sound crazy but I felt the need to test again subconsciously because I overthink my symptoms or lack thereof.. I'm currently 7w4d, at 5 weeks i had an ultrasound because of ectopic pregnancy scare and blood drawn and was over 14000 and thankfully they saw sac in uterus but no baby so at 6 weeks i had another ultrasound where I saw the baby and heartbeat. I have been very sick vomiting every day and tender breasts but for the past 2 days I've felt much better, still nauseous but nowhere near as bad. I know symptoms come and go but my Dr did tell me to let him know if my nausea disappears, today I decided to take a test and it's still positive but the line is much much lighter. is that normal or cause for concern?