Please help me, I am so scared & worried?

Since Sunday I have had severe diareah & nausea, I wasn't too sure what the cause was, whether it was a heavy night out on sunday on the junk food I had been eating or just a virus. Either way I have been feeling terrible, I have managed to eat a slice of toast and some soup since sunday. I feel slightly better now but I have not had much sleep and I have horrible stomach cramps. The thing that is worrying me is that although I don't feel feverish, I have had terrible night sweats. The past 2 nights I have woken up and my bed sheets and clothes have been soaked in sweat. I even took my clothes off and opened a window and I still woke up covered in sweat even after and hours sleep. I am on antidepressants which I haven't taken for 2 days as I wouldn't have been able to keep them down but I don't think not taking them would have caused it as I often forget to take them and don't get this. I am very worried as I have heard it can be a sign of cancer.. please help me? or has anyone else had this after having a stomach bug?