Three positive pregnancy
tests cannot be false unless you are on hCG
medication. You can get a blood test
for pregnancy, if you want to be pretty sure, as this is fool proof most of the times. Wait for your period and if you do not get it, if you have regular 28-30 day cycles, see a gynecologist for further management. You may get a trans-vaginal sonogram after 5 weeks of last menstrual period when a pregnancy can be very well diagnosed. Good luck.