HCG test result opinions, please!

Hello! My fiance and I have been TTC since May and it appears it's FINALLY happening! I had a check up and my doctor did a blood test just based on my symptoms. Here's a break down:

I had 28-day cycles, and on CD23 I had dark spotting. Nothing afterward. But I started being really lightheaded and sensitive nipples.

On CD 26 my HCG was 3, however even though it was early, it was still promising. So I went back 48 hours later and it had jumped to 21!

But the number was still low, so she asked me to come back in 48 more hours. Unfortunately, I had to work during the 48 hour mark, so I took the test at 45 hours.

I just got the results today on CD 30 and it was only 32. A calculator said that was a 57% increase and I've been terrified. I read the you can still have a viable pregnancy with a duplication rate of 35%, and I'm hoping that's true. I'd love to hear anyone else's experience for peace of mind!! ❤️❤️❤️

If all goes as planned, we'll be welcoming our first child on October 3rd, 2019!