lines getting lighter 5 weeks 4 days

Alright so I know you aren’t supposed to test after 5 weeks but I started loosing symptoms today so I took one. I am 5 weeks 4 days. I had an ultrasound yesterday and I was measuring at 5 weeks 3 days.( right on time). We seen the “beginning” of a yolk sack as the ultrasound tech put it. Today I woke up and have absolutely 0 symptoms and don’t feel pregnant at all. The top picture is from yesterday morning at 8 am. The second picture is from today at 3pm. I know that HCG changes but i’m extremely worried i’m going to miscarry or have a chemical :(