Uuah, that's a question not easily answered. Basically there is a lot of stuff going on in the background of your safe file, which should NOT be going on. And this stuff is clogging up your game, to the extent that other stuff breaks - in your case SS2 quests. There IS a chance you can recover your game, but there is also a chance this save file is f***ed permanently. If you want to try to recover this save file - and you should try that - please make a new topic in the Help section (so we free up this space here for patch-related discussion) and we might be able to assist you.
Preliminary steps you should also take immediately:
1. Move your character to an interior cell where nothing is going on (like Home Plate in DC, if you have that) and let them sit there for half an hour or so. Then make another save.
2. Make sure to keep all the saves you still have from this playthrough. Back them up.
3. Start reading up on the technical stuff involved here:
Read the whole damn thing, but pay attention to Section 5 especially.
4. Download and install Fallrim Tools. Link is in the article postet above.
5. Start hoping the problem startet recently, and you have a fairly recent save game to roll back to.