What Causes Scanty Menstrual Bleeding?

Hi I m 19 and ive never actually been to an ogbyn before I just have a question regarding to my monthly friend. A year and a few months ago my period was irregular it would leave for 3-4 months and start out of the blue but it got to the point in which it was regular and I got it every month on the 24. After that happened and a few months went by again the date changed to the 15th of every month and then it stopped like completely for 3 months now it did slip my mind I might be pregnant but I did multiple test and blood work nothing popped up. Yesterday I received my period but it s not normal it s like I m spotting, it s the lightest I ve ever had it And I m usually in lots of pain wen its gone for long and nothing, no cramps no sickness nothing but the fact that it s super light I m just a little worried. My family has a history of not being able to Conceive and also problematic births to the point where they almost died. My mom went through menopause at a very young age and I ve been told before I might have trouble getting pregnant. so I just want to know what could be happening to me. If u could tell me a few things that might be going on with me.