Repeat blood test to confirm??

So I just got off the phone with the doctors who I literally had to hound to get my blood tests back and they said yes I'm pregnant but it was a little low so I have to come back in a week for repeat blood work just to make sure the numbers are spiking up like they should be. They say it's low because I'm early and not to worry. 4 weeks is still really early but I can't help but be concerned that the numbers won't spike up and this pregnancy will all just be a dream. Did anyone else's doctors say the same thing?? 😔