Over This Past Weekend, I Experienced A Situation That Concerned

Over this past weekend, I experienced a situation that concerned me. I was standing for a period of about 5-8 minutes when I started to get very dizzy, short of breath, extreme sweating and fluttering in my chest. I sat down, dropped by head to my lap and attempted to stop the dizziness. After I moment I attempted to rise by was overcome by the dizziness and fainted back into the chair. The ladies that were assisting me attempted to give me water however I experienced severe nausea and vomited on 3 occasions. I am female, 62 years old, no prior health issues but take furosemide, atenolol and synthroid.