Saves Not Loading in game after latest update and broken game.

Pchsolie  You can if you want to since they aren't any good anymore.  That's up to you.  Tbh, if it were me and had what you have had happen, the best way to start over is to rename the "The Sims 4" folder and start a new game there rather than just start a new game in your existing folder.  A new "The Sims 4" will be created.  That way you start over fresh.  Once you've started the new game and made and placed the mandatory sim, just save and quit.  Then move the tray and mods folder over from your original "The Sims 4" folder.  Restart the game and play on.  Once you've moved what you want to keep from your old folder, then you can delete it if you want to.

Since you're a mod user, one thing I highly recommend you do is to go through your mods folder and make sure everything is updated and actually works.  You'll probably be surprised what you find if you have a lot of CC.   I know I did when I did it.  I used to use a lot of CC but when I lost my long term save a couple of years ago to corruption, I decided to clear out all the CC I had that I didn't use on a regular basis before I started over.  So, I used Sims4Studio (S4S) to look at everything as well as looking at it ingame.  I was really surprised when I found over 100 items that were broken and many which didn't even show up in CAS or the build/buy catalog.  In the end, I took out about 3/4 of the CC I had.  I was really surprised when my game loaded a lot faster and plays so much smoother than it did before.  The time investment was really worth it for me.  And it might be worth it for you if you had a lot of weirdness going on in your game previously. 

Hope this helps.

Ok thank you so much for your response! Do I just delete all my saves? I'm scared that if I try and start over the same thing will happen again. And my game is having so many bugs beyond the load game issue.

Pchsolie  Tbh, what I think has happened is your save has corrupted, and the game is no longer seeing a valid save file.  If you don't have any other valid saves in the save folder, then the Load option won't show up, just like when you start the game for the first time.  What I think happened when you tried to load the old save is that the game couldn't find it and defaulted to the last valid save file in the folder which was your new save.   So, you are going to have to start over with a new save.  Hopefully, you've saved the lots and sims you made to your Library.  That will at least give you something to start over with. 

Why your save corrupted, I have no idea.  There are a number of things that can cause a save to corrupt.  This thread outlines many of the latest corruption issues: [PLEASE READ] Save Game Corruption | EA Forums - 5037272   I suggest you give it a read to help you going forward as some of the posts include ways to avoid corrupting saves.     

Hope this helps.