False Positive?

Is a false positive possible? I was 3-ish weeks late so i bought alot of hpt. I took 6 and all said negative. So the last hpt i bought   Was the cheaper kind from walmart the .88 cent ones. I took that one and said negative but i looked at it again the next morning and it was a positive. Then about 2 days later i went to the restroom because i felt wet. Well it was blood. Did not see anything that indicated a fetus. I never miss a period so i was worried if it was a miscarriage