It sounds like you may have acute gastroenteritis. The most critical step is staying hydrated; please start drinking Oral Rehydration Salts (ORS) or clear fluids frequently. For the fever, you can take Paracetamol. For nausea and vomiting, a generic medication like Ondansetron can be helpful, but it is best to consult a healthcare provider for a prescription. Avoid taking self-prescribed antibiotics or anti-diarrheal medications, as they can sometimes worsen the infection. Rest well and stick to a bland diet like bananas, rice, or toast. If you cannot keep liquids down or symptoms worsen, please consult a doctor.