Randomly changed my name at work after dragging for 7 months - is it strange?

Speaking as someone who interacts regularly with many colleagues in different departments who I don’t work alongside in the same office, I don’t think you need to say anything. It is not anyone else’s business whether or not you change your name, and if so, on what timeline. If anyone asks it is totally fine telling them but otherwise I don’t really see this as one of those things that needs addressing (unless your workplace doesn’t have an email re-direct set up if your email address has changed too).

A lot of the people I work with just include a line above their email signature along the lines of "Please note my email has changed to..." Unless your maiden name is part of your email in some way and/ or it won't redirect, I don't think you need to say anything.