Saw a dr say you can't have diarrhea and constipation at the same time on a question i saw... but can't you have both with a bowel obstruction?

Absolutely!: There is such a thing as having a constipated bowel around which liquid stool passes. This is a very uncomfortable situation. The overall solution is to manage the constipation problem so that you have a normal, brown, formed bm daily. In the mean time, you may have these strange attempts of your bowel to overcome trouble areas. True bowel obstruction is a medical emergency -- nothing comes out!

Diarrhea/Constipatio: If you have bowel movement and without having abdominal pain, unlikely you have bowel obstruction. You can have severe constipation that leads to obstipation/stool impaction. Stool becomes hard at the distal end, but soft/liquid at the proximal colon. The liquid portion will leak, which resulted in diarrhea.