Terrified of losing it

Allison
Found out I was pregnant with a BFP last weekend. Tested negative at <a href="https://glowing.com/glow-fertility-program">IUI</a> follow-up on 15dpiui but never started so I took a test on 17dpiui and got a BFP (faint line on wondfo and Pregnant 1-2 on digital). But now I'm scared it's going to end in loss. I had a blood test done on 18dpo and it was positive but progesterone was low and HCG was only 88. The nurse said there was nothing to worry about but of course I have googled and it seems most people's levels are much higher by that point. I've also been POAS like crazy to see if lines have gotten darker as it seems most tests I've seen from other people are so dark they pull color from the control, but mine don't seem to be getting darker. I'm attaching a pic of my tests from the last few days. I have follow up blood work today and will find out tomorrow, but i just have a sinking feeling it's not going to stick. After almost 2 years, I really thought this was it. I appreciate any insight anyone can give. Thanks!!