Unwell toddler

My little one is so unwell and it came on soo suddenly. I’m really confused as to how he caught a virus as he is not in nursery and we haven’t been anywhere but he has a high fever with runny nose which tonight has progressed into vomiting and diarrhoea. He hasn’t been sick like this before so just wondering what the plan of action should be? Will give him some medicine again when he’s out of the bath (as he was full of vomit) but should I take him to gp or will they just dismiss it? I’d rather not drag him there if that’s the case. I know it’s so normal for kids to get sick but like I said this is the first time it’s been like this so I’m just one concerned mama 🥺