Sims stuck on loading screen forever

MariMonay98  When things work when you test them alone, and then not when you put them back together in the mods folder, that can happen.  What you probably have going on is two or more mods are conflicting with each other.  That even happens if they have been together in your mods folder for some time.  Out of the blue, the game does something like what you have going on.  Any change to the game such as updates, SDXs, and new packs can trigger that when the game code gets changed. So, my advice to you is to, first, make sure everything you have is up to date and you are using the most recent version.  Second, look at what each mod does or is supposed to do.  Having two mods that essentially do the same thing can be a prime cause of conflicts so you should compare them and may a decision to use one and remove the other(s).  Third, for the ones you decide to keep, make sure they are actually doing what they are supposed to do and haven't stopped.  Over time, a few will stop working but never give you an indication that has happened.  Forth, after doing all that, test what's left as you did before.  But do it in smaller increments after you test the first half.  Maybe do 3 or 5 or so at a time rather than 10 until you've either found the conflict or gone through everything.  Fifth, test your CC too.  Broken CC can cause issues one wouldn't think they could sometimes.  Make sure everything shows up in CAS as well so testing things like all your makeup together rather than one file at the time helps so you can compare the number of files in the test batch with the number of thumbnails that show in CAS.  When there is a mismatch, you've got a broken file.  And if anything shows up with a thumbnail that is obviously broken, you should remove that as well.

My only remaining bit of advice is this.  The less you have of either mods or CC, the better the game will run and the fewer problems you will have.  Look at what you actually use and get rid of something you've never used or used only just once or twice.  In the case of mods and CC, the less you have, gives you more time to actually play the game since you don't spend your time troubleshooting after the other.  

Hope this helps.