I have just had this same thing!! And boy was i freaking out lol!! I have had mine for 9 months now and bled for almost 8 months straight then out of the blue it stopped and random pg like symptoms popped up, I did a test and it was neg, was going to do another but started bleeding again yesterday, so 8 months of bleeding, 3 weeks of nothing and then started again, LOVED the period free bit!! Im sort of thinking, it was hormones stuffing around (pg symptoms etc) but may also be my body finally getting used to it. Def try doing a test or two, just to put your mind at ease, and if your still worried, just visit your gp