I recently have been hospitalized for overdosing on doxepin. Since then I ve had a couple late bowel movements. The first taking two days but just a small amount. And and the second concerns me the most. I was constipated and my stool came out thick or hardened and black. And by black I mean no shades of brown or green. It was shades of grey black. I am wondering if my overdose of prescribed doxepin caused this to happen and will it go away?