Hi! I'm a French Canadian. We don't write "sacres" (unless you're on a social media). If you really want to write it, you could say "Je m'en câlisse de l'automne". You can write "sacres" in different ways ("caliss", "calisse" or "câliss"). Don't forget that this "sacre" is coming from the word "calice" and there isn't an official way to write it because it is mainly used while speaking. "M'en" is reflexive but it's also a "locution".

The translation is more I don't give a damn about autumn. There are a lot of expressions on that scheme : je m'en + verbe. Which most of the time are just some very imaginative way (and also quite vulgar) to say I don't care. https://www.italki.com/question/363251