I don't know from personal experience but I think it is fairly common to get a positive result even after several negative results. The reason is that if you are pregnant, it can take awhile for your hgc levels to get high enough that the hpt will show positive. So you may have just tested too early for the pregnancy hormones to show up. I would wait another few days and if you don't get af, test again. Or you could go to the doctor's for a blood test because that is more sensitive than a urine test and you would be more likely to get a positive result if you are in fact pregnant. I have heard of people getting negative hpt results up until they are 3 months pregnant! So don't get discouraged just yet! Good luck!