Red stool from nyquil or bleeding ulcer?

I have been sick with a severe head cold for the past three days and havent eaten much. but i have been taking nyquil, (in the recommended dosage of 30 ml every 6 hours), and my stool is runny, green with red tint. im hoping that the red is due to the nyquil color, but i am almost positive i have an ulcer and have had it for a few years. someone give me an opinion. im freaking out here,