Hcg low at 4 weeks?

I had my HCG tested at 4 weeks, which I know is VERY early, but I had a 23 week loss this year and my dr has been very kind and allowed me to do a blood test as soon as I tested positive to help ease my mind.. getting pregnant again following such a devastating loss is hard on my mental health! Anyways, we did a draw at 4W and my HCG was 29 and then 48hrs later (4W2D) it was 89… which I know it’s good that it doubled, but we did blood work my first pregnancy in the 4th week (there was an ectopic scare) and my numbers were 1440 and 3330 - so I’m curious if anyone has had such different HCG levels with different pregnancies?? I understand I can’t compare the 2 pregnancies but I just am curious to hear others experiences 💘