Extremely painful cramps in rectum during period

So this is the first period that I've had in 2 years and in the past I have a fairly regular flow to light flow, but I'm very heavy this cycle. This cycle has also given me the worst cramping in my 12 years of having a menstrual period. I'm also having cramps that start in my lower abdomen that move through my rectum and vaginal area. When it happens it stops me in my tracks, sitting is uncomfortable, as well as wearing a tampon. This has happened a few times in past periods also.