I know this sounds a bit daft but I did a pg test last night, fairly early in my extremely irregular cycle (if you can call it a cycle) and it came out with the control line and a very faint second line - really faint but definitely there. Then I did one this morning as that one wasn't very convincing and the one this am (with an x for pg) looked pretty much negative - a sort of shadow instead of a line. What's going on?! Can you get false positives or only false negatives?