Okay so here's an update. I've uploaded a pic of the 4 Tesco tests I've taken so far. The top one was the first one I took the day before yesterday, the second I took yesterday morning, & the third & fourth I took earlier on today. The first two, the lines appeared within the timeframe. Within a min I could see a cross even though the line is thin & very faint, although it is still blue in colour. The 2 I took today took a little longer, which made me think that maybe they are evap lines. I'm just not sure anymore. Cause my thoughts are surely if it was a positive the lines would be thicker & darker today than the first 2 I took!  this is driving me crazy!