I've been having very light brown spotting for 10 days. My periods are irregular but the longest cycle I've had this year is 44 days and now I am on day 46 with no period. Today I started noticing some mild cramping on my left side, and I have felt a little bit nauseous and bloated on occasion, but otherwise I feel normal for the most part. I have taken multiple pregnancy tests and they are all negative. Should I assume I'm not pregnant, or take another test in a few weeks, or what?