Sims 4 Holiday/Calendar Glitch

For the last 3 weeks I've been struggling trying to fix a holiday/calendar glitch. Holidays that are scheduled to appear on the day they are created for are appearing and starting on the day before they are supposed to. For example, Harvestfest is supposed to be on Thursday (fall - extended seasons length, but have tried regular length and both are having this issue) and while it still shows on the calendar that Harvestfest is Thursday, it's starting at 6am on Wednesday. But doesn't show a holiday for Wednesday. I do have mods and CC but have gone through it all testing by putting everything back in little by little. I don't have MCC or TOOL. I have spent the last 3 weeks cleaning everything up: the entire Sims 4 folder. Repairing, re-downloading, going on every forum, trying every trick and dealing with many other bugs on the way like the recent save progress error. How do I fix my game?? I've been simming since the first Sims, have spent many hours fixing many problems and glitches, but this got me. Any help is welcome!!! 

Sorry if this is in the wrong thread.... I just am at a major loss!!