I Have Been Fighting A Cough For 3 Weeks. Saw

I have been fighting a cough for 3 weeks. Saw a primary care Dr 12/31. Chest was pretty clear. Prescribed a "cheratussin" with codeine at night, over the counter tussin during the day
. Also, been taking cough drops regularly. Not much better 7 days later. Tonight I had 2 bouts of diarrhea but with blood in the stool. Bright red. Relatively significant amount when wiping. Does not appear to be any hemorrhoids present. Could medicine have that side effect?