Hello I'm A 13 Year Old Girl. So Two Days

Hello I'm a 13 year old girl. So two days ago around 3 pm I started throwing up every 30 minutes or so, I couldn't even keep water down. That night I slept pretty well although I woke up a few times but in general everything was fine. Yesterday I felt better only hungry so I ate a toast and a cup of tea for breakfast and a bowl of soup for dinner. That day I drank less than a litre of water. But around noon whenever I sat down or stood up my head would start to hurt andd it felt like daggers were piercing it mostly on my right side. And this morning I woke up about 40 minutes ago and I feel pretty nauseous, my stomach feels weird, my throat isn't dry but there's this disgusting taste that I can't really describe.