So confused!!

Jinny • Mommy to 3 beautiful boys, one who is in heaven. Ttc for my rainbow baby! Trying since February 2015. 27 years old.
So my last menstrual period was 1/09/16. I have a longer cycle of 34 days. On 2/05 I decided to take a htp and saw a faint positive. The reason I took it before a missed period was because of symptoms. Yesterday I took another hpt and it came out faint again. Today I took a digital htp and it came out PREGNANT. reason why I'm confused is because I got my blood drawn to check my hcg levels. I have some cramping and back pain so my doctor wanted to rule out ectopic. My blood work came back and I'm pretty low at 13. I'm not really sure how far along I am at this point given that my cycle this month seems much shorter. I ovulated a lot earlier maybe?? How did I get a positive on a digital if I'm only at 13?? Doesn't make sense. I'm also going in a few days to check my levels hoping it doubled! Hoping someone can encourage me with similar situations! Thank you!