What Causes Light Period And Fluttering In Stomach While HPT Is Negative?

I had a period early November that was light and so back in December I didn t have a period my tubes have been clamped for two years at this point and the jan rolls around and I had a light spotting like period for two days and it was the same this month and now I m getting very low tummy flutters and this is after a pregnancy test in jan to ease my mind that came back negative, I m good with being paranoid I just like to be prepared