What Could Cause Black, Sticky Stool If I Haven’t Taken Any Laxatives And Have A History Of Irregular Bowel Movements?

The day before yesterday I worked up and had to poop. It was black and sticky and that evening I had to go again this time it was more but the color is the same I haven t toke any powder to help me poop. But I haven t been eating much or sleeping since I lost my husband last month. But what could has cause it to be black and sticky. Usually i am sitting there straining to get it out of me but when I been drinking gluten t milk my poop is going good. I mean I haven t had one yesterday. Which my bowels is always been off when it comes tou bowel movement. But last month I did fall and it the sidewalk but I fell on my right side. My right leg has been giving me pr