Low hcg and I need reassurance 😞

My last period was July 22nd. According to ovulation tests I ovulated August 12th. I got my bfp on a FRER on August 22nd but clear blue digital was negative but I was fine with that since AF wasn’t due til the 26th. Today, the 27th, clear blue digital was positive. But I still wanted to get blood work for confirmation because my frer lines were barely darker. My levels are at 16 and I’m feeling really discouraged about that number for being 5 weeks. However, I went on website called Americanpregancy.org (i think) because when they calculate your due date they take your cycle length into account. My average cycle length is about 34 days so they put me at 4 weeks. I just need someone to tell me that they had hcg levels this low at 4/5 weeks and went on to have a healthy pregnancy. I go back in 2 days to have my levels checked again but I’m not feeling very hopeful right now.