Why does mead make me drunk instantly? (27F)

Ello. Im asking this, drunk. I dont understand it. Ive had always had a high tolerance and drink my fiance under the table when it comes to whisky, rum, vodka, etc. But when it comes to mead, a few sips in and im gone, red-faced, and giggling like a schoolgirl. Why does mead get to me so easily? It’s only 18%!