Hcg level 41?! Is this it?!

I had my pregnancy blood test at the clinic today and the doc called back saying “Congrats you’re pregnant. You’re hcg level is at 41.” But he also said to make sure to be cautiously optimistic because it’s early and I’m going back in 48 hours to check my levels again. Thoughts?! Of course I’m over the moon but also wondering what that number means?! Ahhh I just want to be in the clear!