What Causes Constant Nausea Along With Vomiting And Abdominal Pain?

I have been having ongoing issues with constant nausea and vomiting for the past 6 months along with loose bowels, rapid heart beat, fatigue, poor memory and abdominal pain. Since yesterday I have been feeling a bit off balance as if I m drunk, everything seems a little fuzzy. I woke up this morning with the most immense throbbing headache, i vomited a lot and literally couldn t move for a few hours. I am still feeling like my head is not quite attached to my body and I have just opened my bowels and passed a large amount of foul smelling yellowish water. I have been seeing my GP regularly and am waiting for an appointment with gastroenterology (15 weeks) I am taking antiemetic medication to help with the nausea but feel like I am feeling worse than ever at the moment, I m desperate to know what is wrong with me.