False Positive

Hi gals, I'm looking to see if I can get some answers. I started taking Spirolactone for acne two days ago. I know I have to be really careful about not getting pregnant. So this morning I took a pregnancy test it showed positive (I think the line was extremely light) now I just took another test and it showed negative. Can spirolactone cause a false negative? I'm wondering since I have only been taking it for two days, and in the morning I had a positive result and not later in the day. Any advice would help.