Hi I Was In An Car Accident 4 Days Ago,

Hi I was in an car accident 4 days ago, where the flipped upside down, but I had a seat belt on and curled out virtually unharmed. Every since I haven't able to complete a bowl movement, accept maybe a partial one time one movement that took 30 minutes to do with minimum results, idk if I should go to the er (cause I never went i felt OK after the accident) or take some kinda laxative? Help