Evap lines?

I have oral surgery scheduled for tomorrow and was asked to take a pregnancy test bc I can not be put under. I did it bc I was asked and didn't think anything of it. I thought I saw a line but have permanent line eye from TTC for a year now. When I went back a couple of hours later there was a definite line. This happened 3 different times with 3 different urine samples. I had very light bleeding for 2 days and then 3 days of very very light brown bleeding 3 weeks ago. I assumed it was a period but my breasts and tummy have been firm and tender for about 2 weeks now. I don't know whether to be cautious and say I am pregnant or just go ahead with the surgery? Has anyone else had repeated evap lines (assuming these were evap lines)?