Thank U L Am Vomiting Up A Large Amount Of

thank u l am vomiting up a large amount of dark brown liquid my stomach hurts and I am so Nausea> l am also very dizzy when l stand and feel as if l am going to pass out . l have also fever l cannot drink any liquid because of my nausea. I havn't felt good in several weeks . what do l need to do ? again thank you for helping me also l am a male 70 yrs old I had heart surgery back in 2005 5 bypass. I am not on any type of medicine except 1 Aleve a day .