Light period like bleeding???

So I started spotting yesterday it was really light and stuff. Then this morning it got a little bit heavier but not really heavy just like a light period and the blood is fresh. Well I decided to take a pregnancy test and a little bit of blood was in the cup when I took it. Well it looks positive to me Cuz a vvvfl appeared on the test within 3 minutes but I'm just curious if anyone else has taken a test while bleeding and it turn up positive and you was pregnant or if u took one while bleeding and it was positive and you was not pregnant. Please someone let me know. I just wanna know if blood in urine can affect a first response test and it be false positive