Feeling slightly sick / digestive issues after a day of high-protein diet?

Hello, I began doing P90X two days ago, and I changed my diet regimen to include mostly lean meat and a lot of protein, and cut out a lot of carbohydrates, which I had been previously eating a lot of through cereal, pasta, etc. I am a relatively healthy weight at 160 and 6 feet tall, but I am trying to shift my diet to a lot more protein oriented. It worked for my body and I felt nothing but satisfied until this morning, when I felt pretty sick and had diarrhea. I feel back to normal now, and I'm wondering - is the digestive issue due to my change in diet so quickly, or is there a deeper problem with my protein intake? If the problem is not the latter, I want to proceed and battle through the trouble to shift my diet entirely.