Help- Sims 4 Not Responding

A broken lot won't stop the game itself from loading. You're going to need to go through the links I posted, systematically. And consider adding back and testing only the CC you actually are making use of, not things you downloaded just in case you want them someday. Reorganize by creator to help find duplicates, which are more likely the larger your folder is. Delete anything that might be a merged set of CC you can't identify.

Thank you for the advice! I haven't been going into my old save with the Gallery lots since I'm worried it could cause problems- when I can get into the game, I test in a new save. Usually, though, I'm just stuck on the title screen forever with the app not responding and I can't play any saves at all. Could deleting my old save with the Gallery lots be helpful, or do I not need to do that?

I've checked for known issues, and I'm planning on testing all my cc soon and checking if the game works without it. I think I might just have too much cc with the new medieval stuff I downloaded? I'm really not sure since the game initially worked fine with the new cc and only stopped working after I downloaded a bunch of Gallery lots and went on Facetime while I played it, and as I've been testing the game will occasionally work with just my medieval build/buy or gameplay folder, but usually it doesn't. There doesn't seem to be any pattern to when it works vs when it doesn't, and now it's not working at all with my old cc, which is an issue I've never had before.

Yes, too much CC can mean your computer just can't handle it. There are also broken Gallery lots, so you need to be testing in a new save, not the one you installed Gallery lots into.

Do check for known issues in Previously Broken mods and CC and Broken & Updated Mods & CC. 

See vanilla and 50-50 testing for testing methods. 

I removed my whole mods folder today to make sure the game worked without it, which it did, and then put it back, and I also cleared my cache. I tried batch testing all my medieval cc to narrow down the issue, but it never worked, and now the game won't work with just my previous mods either. I start the game, it does the light blue title screen, freezes, and stops responding pretty quickly so I have to force quit. Does putting too much cc in at once cause the game to crash? My folder is about 41 GB with the new medieval stuff. If anyone knows how to fix this please help I'm very lost!!