Celexa

I was put on this new drug called celexa. I have been feeling stoned for a while. My eye sight is fading in and out, I'm tired, yawning, antisocial, no concentration and my weight has plummeted to 110 pounds. I haven't weighed 110 pounds since freshman year. Multiple people have asked me what is wrong with me. How do you tell someone the reason your stoned is because your taking this drug prescribed for you?