My friend had a false positive or two!! she felt a little 'not herself' for ages and ages and she was still getting her AF as regular a she always did got encouraged to do a test as someone said AF can still visit even when pregnant (though i think its rare!) and she got nothing but negatives it was until she got taken to hospital for another reason that she asked them to check and scan her! not only was she pregnant but at that point was nearly 6 months gone! she never missed a period and had all in all 11 negative pregnancies tests (clearblue's, first response's all good ones) it was like her body was just not acting pregnant at all! obvioulsy she was and her ds is now nearly 6!! its a bit odd how these things work sometimes!