4w+3D worried 😢

Quick back story. I have 2 daughters already but struggled to conceive this time. Took over 3 years with a chemical during that time. I’m now 4 weeks 3 days. 2 positive tests and blood draw confirmed but hcg was low. I keep getting cramps which I know is normal but I’m worried sick. And today my resting heart rate has dropped 😢 Drs appointment isn’t for another 2 weeks. I know if anything was to happen they wouldn’t do anything at this stage anyway I’m just so nervous 😥

Anyone had similar experiences?