Calendar Glitch: Festivals/Holidays Have Shifted & Duplicated

I've never posted on this forum so I'm not sure if I'm doing this right but basically my calendar has glitched. Just in case the info helps, my seasons are set to 2 weeks. Anyways, these are the glitches:

1.  The calendar has gone back about a week. I haven't lost any of my Sims' progress, but the calendar says it's only 3 days into Fall when I know my Sims were previously 9/10 days into Fall because they had just celebrated my Day of the Dead holiday (which has also reappeared).
2. The festivals have shifted. For example, the Thinned Veil festival is no longer every Wednesday, nor does it have a set schedule. Now, its sporadically set on seemingly random days; The next one is on Friday, then the following Wednesday, then the following Monday.
3. Some festivals have duplicated. For example, today it says there are 2 Flea Markets and tomorrow there are 2 GeekCons. It also says that today is both Talk Like a Pirate Day and The Lottery, which I think I'm the most confused by because I know it should be impossible to have 2 holidays generate on the same day.

I'm not sure when exactly this happened but I know had been testing out CC doors when it did, and I had restarted the game maybe 3 or 4 times while in the process to download new ones/delete ones I didn't like. I can't see how a door could break my calendar, but I also don't really know how stuff like this works admittedly.

I don't know if y'all need to know all the mods I have, but the bigger ones are MCCC, adeepindigo's Education Overhaul, a bunch of Lumpinou's stuff including RPO, SonozakiSisters' update of LittleRedSonja's Houses of Witchcraft, Zero's Civic Policy Overhaul, and a bunch of LittleMsSam's smaller mods and bug fixes. The only mods I have that have anything remotely to do with the calendar is ClaudiaSharon's No Festival Notifications and Bosseladytv's Fewer Festivals but seeing as I downloaded those over a week ago and this issue has only just now cropped up I don't think they did this (though I did delete Bosseladytv's in the hopes that it would help and it did not).

If someone could help me fix this or, if that's not possible, figure out how this happened at all, I'd be very grateful. Thank you so much!