Hi!
If the pregnancy test was negative, you are probably NOT pregnant. I ALWAYS recommend repeating the test though. Sometimes the very low dose pills can result in a bleeding that is so slight that it looks more like an infection than a period.
It is never a bad idea to get a check up too, though. It could also be something like bacterial vaginosis or yeast, or worse, an STD.
I hope this helps!
Dr B
Discharge isn't a good indicator of pregnancy, as it's totally different for everyone and every pregnancy.