Sorry to hear you're having issues, it could be a few things. Have you installed any content lately?
But maybe give these things a try
Check the particles folder (C:\FeralHeart\media\particles) and look for duplicates like _0, _1, _2, _3
If there are duplicates, delete them.
Try running FH as an administrator and see if that'll work
Let us know if that fixes it or if it persists, if it does you might need to backup your important files and reinstall if it doesn't fix itself.