Recent Dizziness that makes me feel like i'm going to faint with anxiety and palpitations

So my dizziness all started with a inflamed hair follicle that lead to an abscess on my underarm. I had to get that drained and packed and was put on Bactrim (antibiotic)... when I left within hours I felt like I was going to blackout and faint. It went away after I rested. Since then i've been getting dizzy and feeling like i'm going to faint at random times. It comes with anxiety and it's terrible! I've never felt like this before. I know its not from being hypoglycemic cause i constantly eat, my blood pressure and pulse is within normal limits and the results of my CBC and Thyroid panel have came back normal as well as my 12-lead EKG. Like today after 20 minutes of working out I felt like I was going to black out again... but I had just ate 1 hour before. Sometimes I get the feeling while eating, others while sitting, and then when doing active things... like i said I feel this way at random times... My mother told me that her friend has felt dizzy lately too and thought perhaps it may be due to the H1N1 vaccine. I too have taken that months ago... who knows. :'(