Slow to rise HCg levels-please help!!

Lindy
Anyone else not have very strong lines in early pregnancy?? I tested positive on Saturday morning with FMU and then tested again today with FRER and the line looks the same or maybe even a touch lighter? I'm trying not to be paranoid and according to my <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> AF was technically due tomorrow...
UPDATE...On Monday 6-20 my beta hcg was 33 I went back on Wednesday morning and it was only 39! I'm freaking out but still trying to remain hopeful 🙏🏼😞 Doctor says I could just be really early and I get retested next Wednesday....any insights from anyone?