What Causes Light Headedness, Dizziness And Difficulty In Breathing?

I have pre-asthma (pro-air) and high blood pressure (lisinopril). I have been taking a herbal supplement called prelipid for 3 days. Today, I was light headed, dizzy and had trouble breathing - my chest tight on my right side when I inhale deeply. Checked my blood pressure and it was okay. Thoughts on what could have caused this?