Please read!

Top pic is today’s test, bottom is the 3 I took yesterday. Is it normal that the line isn’t any darker (and even a but lighter) than yesterday’s? None of them were taken with FMU. Long story short I took femara 8/5-8/9. Started bleeding 8/26-8/30 so thought that was my period. Been feeling different so took a test yesterday (well 3 diff times of day lol) and had vfl. But today’s looks a bit lighter than the others. Should I worry? I had a blood test today and an appointment with OB tomorrow since they “arnt sure if this is a viable pregnancy “. Please any input would be great!