How soon should I get blood work done?

Sydney • Mommy of a 2 year old boy and a 6 month old girl ❤
I got a positive about two days ago in the middle of the day and I'm just wondering when I should call a doctor for blood work and yada yada? I wanna make sure I pass it because I got a negative blood test on Saturday but then finally got my first positive hpt on Monday with a first response. 
Here's my test^^