I am experiencing an extremely heavy period with a lot of large blood clots (almost looks like pieces of liver) . I know that sounds gross but I am concerned because I also have a lot of abdominal pain and an it also feels like my insides are pushing against my rectum. I feel like I did just after I gave birth. I didn't think I was pregnant ; because I just took a pregnancy test last week and it was negative. My periods only come every 2-3 months which has always been normal for me and I always have a light, almost non existent flow. I feel like I may be having a miscarriage with the size of the clots.