A bit concerned college student?

'There's this stomach flu going around comp. I was one of the first to have it, and I had one of the worst cases. I spent the entire nightt 'coming out both ends' until I was completely empty (and still wretching, lost my voice for 3 days). They doped me up for a day and I got back to school and work. What worries me is that I have no appetite, my stool is a weird pale yellow, and I constantly feel like there's a boulder in my belly. It's been nearly 5 days since that happened. Should I see a doctor? I really can't afford, so I'd rather not if it's nothing serious, which I hope.