How long does it take to lower blood pressure by eating healthier?

Mine has been abnormally high for about a week .

I have been having one sided headaches, and pressure behind my eyes all month.
So it prompted me to check my blood pressure.

I will be getting an eye exam soon and will go-to doctor as soon as I find a new PCP.

I don't eat too terribly. I snack and fruit and eat oatmeal for breakfast most days . Dinner varies between healthy and unhealthy (had pizza yesterday 😞)

Again, I know I need to see a doctor and I will. I just couldn't find info from a reputable place online, at least from my phone I couldn't see reputable sites..just blogs about it