No sign of period, been taking pregnacare contraception tablets..?

I've been reading up on the pregnacare tablets and the reviews where good, so i bought some, well normally my period is 31-33 day cycle, my last period was 23rd may, yesterday when i wiped there was a tiny bit of blood, but since that nothing! lately ive been tiered all the time, and feeling sickly, im going to take a test tomorrow, fingers crossed i am pregnant! ...has anyone else had this while taking pregnacare tablets?