you are tapering too quickly. I highly recommend this book:
Are you overweight?
Do you exercise?
I used to be on this reddit posting this all the time: Read this book
I spent two years trying to get off of Lexapro, which is very similar to Celexa and I couldn't get off. I can't remember if this book talked about this side effect. It sounds like you did a solid taper.
Make sure you read this book: https://www.amazon.com/Antidepressant-Solution-Step-Step-Overcoming/dp/074326973X
I wasn't able to get off, but if you want too this is the way to do it. Half is too much.