Tests not getting darker

Mary • MC 8/20/18. 🌈💙 6/16/19. MC 11/4/19. 🌈 #2 & 3 Berlin due 10/2021 💗💗

I’m 4 weeks 2 days I had a beta HCG done yesterday and it was 136. This morning my tests don’t look any darker. The strip tests are yesterday and today and the FRER is Thursday and today. Any advice or anyone been in a similar situation? I’ve had 2 losses with a healthy pregnancy in between but I’m horrified to lose another.