help help help

Phoebe
I am currently 3 weeks and 1 day pregnant and got my blood pressure done at the doctors today..it came up as 113/91. 
91 is higher than it should be and I am so scared that I will have another miscarriage because of this. 
Does anyone know anything about this? The doctor didn't seem worried he just said he wants to keep an eye on it. I hope it's just because of stress so I can just relax and fix it and not because I'm unhealthy or something.