I have horrible seasonal allergies. today is really bad and i have copious sinus drainage. could that be cause of my bowel movement being mushy tonight? i feel fine except the runny itchy nose eyes and throat

Yes: Swallowing copious sinus drainage could cause irritation in your intestines, causing mushy bowel movements. Try doing saline nasal washes daily during the peak allergy season. It will clear out mucus and debris which collect in your nasal passages and cause irritation and inflammation. You should already be on an antihistamine (claritin or zyrtec) as well as a steroid nasal spray (flonase).