I Am An IV Methamphetamine User. I Use Probably 2

I am an IV methamphetamine user. I use probably 2 to 5 times a day averaging anywhere from .5 to 1.5 grams daily. I know this is a nasty habit that needs to be kicked. Not to mention it's a lot of meth to shooting considering I have A-fib. But I also have been having extremely painful bowel movements lately. Like almost intolerably painful. Could this be connected to the meth use? Or is this something unrelated?