Feel sick after a long run

I did a long run this morning. I was up for a while before I ran. I ate a little something for energy, had some coffee and water, I warmed up and stretched well. Im on a training schedule and this is only the second time...EVER....that Ive run 7 miles (the last time was back in March). Got home, drank a ton of water, then had a protein shake. A little while later, I had a piece of toast, just to have something on my stomach. Since Ive gotten home, I've felt nauseous. It's lunch time for me, but I dont dare eat anything right now, for fear it would come right back up.

What would cause me to feel like this hours after the run? Should I eat something before or after that would help? I usually only feel like this if I work out SUPER hard, to the point where I dont feel like I can make one more movement. I was fatigued this morning, but not to the point where I felt like passing out or anything...