Blood test wrong?

Ok going to try and make a long story short. My last period was September 5-12 and I went in on September 29th because I hadn't been feeling well and thought I was pregnant. I didn't do any at home tests because with my first 2 children I never tested positive on a hpt, it always had to be verified by bloodwork. Well yesterday I was 1 week late for AF and my breasts were tender. Decided to humor myself and take a hpt. Before the urine even got to the second window that pregnant line popped up!! Dark blue! I took another one 3 hours later super dark and instantly pregnant. But my question is, was the blood test wrong? Am I 5 weeks pregnant or am I seriously only like less than 2 weeks?? I have a dr appt on Friday to hopefully figure everything out but was curious if anyone else had this happen?? Blood test negative then positive hpt?? Thank you!!