I don't think its normal. I doubt its absorbing and having and side effect within the first few minutes, but I could be wrong. Perhaps you're anxious, and just thinking about it, idk. Anyhow, long as your healthy and your blood pressure is fine, I wouldn't worry to much about it since the 'weirdness' only lasts 2-3 minutes. In any case, if you happen to be allergic to some ingredient in Natadrol and it keeps acting up, I'd probably discontinue it, but your probably good to go.