What Causes Vivid Thoughts Followed By Nausea?

Hello, I am a 22yr old female. I have been having weird deja vu's followed by a glimpse of a dream i havent had followed by nausia. Thes flash backs make me sick to my stomach. I think i may have had a seizure months ago, where as i felt like i was in a tazmanian devil cyclone, made weird noises and my friend caught me and i didnt know who he was or where i was for 20 seconds. are my new "dream flash backs, deja vu, nasia related and what is the cause. i don't do drugs.