Does your university have a speech and hearing/language department? Maybe they have some SLPs who specialize in stuttering and can help. Avoiding all social interactions will only make things worse but I understand socializing feeling too overwhelming and you need to protect yourself. I would look for an SLP or someone who can help work with you on this but in the meantime, maybe you can join take any kind of baby step away from isolation. Take a small social chance. You 100% care about it more than anyone else does but I know that doesn't really help even if it is true.