Hi, I am due on my period today and it has not arrived (I have long, sometimes irregular cycles and today I am day 36 of my cycle, but have once had a 38 day cycle and last month it was unusually short of around 26 days). I have been feeling nauseous the last 3 days so took a CB test this afternoon (not the best time to test I know), it came up as negative within the time window, but after an hour I went to throw the test away and saw a blue, thin line. Is this an evaporation line or could it be a sign of a positive result? I am not trying to get pregnant, I use condoms with me partner but leaks and splits can always happen! I will test again in the morning.