HCG question

This may be a dumb question, but I don't understand. So I took these tests about 45 mins before I got my blood drawn. My blood HCG was 8. I have another blood draw tomorrow to see if it goes up but I'm not hopeful. I'm guessing it's a chemical pregnancy considering I was 13dpiui when I had the blood draw. But when the Internet strip and Walmart test don't read positive until they have the 25miu, how are they showing positive when my HCG was only 8? I'm so confused. Also any prayers that a miracle happens would be great. I had a miscarriage at 12 weeks in February and now this 😔