Could Dizziness And Extreme Sweating While Having Mechanical Valve Installed Be Stroke?

Yesterday I got real dizzy and had trouble standing up. I thought I was going to fall down. I started to feel like I as going to throw up. I broke out in a sweat and my shirt ended up soaked. I had no problem talking or seeing, no numbness in hands or face and no headache. My blood pressure was 137/87 with a pulse of 62. This was at about 9:00PM. This morning I got up at about 9:00AM and have had a small headache all day. I have heart problem, A mechanical valve installed about 3 years ago and 2 bypasses down. My chlostraall is OK. A very small one. Was it a stroke