VETSCOPE

My cat started vomitting 4 days ago and his bowel is also soft. He has lost his voice due to vomitting but he would still eat continously. I stopped giving him food but gave him water with dextrose powder instead. He started feeling better, he would only poop once but still vomits what he intake. I realized he got some terrible colds and I think he might have sore throat since he lost his voice. Now, I gave him erceflora orally, lots of water with dextrose powder and cold syrup. He is still vomitting when he eats but he was still eating a lot than before. Is it really colds or should I be alarm and need to turn him over to the vet? What are the other home remedies that I can do. Since,it's pandemic, we are only allowed to go out following the curfew.