Is it normal my personality switched for 3 days

Im a very quiet person I rarely speak unless spoken to and ive just always been that way but in 2018 I had 3 days were I was not the same person. My anxiety didnt exist in those days and I was talking so much all day. I was in a new town for those days with new people but that had nothing to do with it. I was studying from a distance and there for seminars, but every other seminar I travelled there for I was my usual anxious self again. I bet it must have really confused my class. I still to this day wonder what caused my temporary personality switch because all ive ever wanted is to be social and not anxious. Ive tried therapy again and again to no avail. Nothing makes the anxiety go away but for those 3 days I was the person I am in my dreams and I fit in with everyone else and I was happy and full of energy. It was extremely strange like waking up in another persons mind and its only happened that one time in my entire life. It was like some kind of sorcery.
How was that possible and is it normal to experience that? I literally had a entirely different personality for 3 days straight. As amazing as it was its a bit creepy too because that was not me.