Yes, all of those things. Some runners are afraid to rest because they think they will lose their ability to run if they don't run every day. They're just neurotic. It's okay to rest a day or a week or a month or even a year. I've been distance running since the age of 13 and it's necessary to rest sometimes. There's no shame in resting, and ability to run will not be lost unless there's some irreversible injury, which is rare for most healthy people.
Not a runner, but for me the feeling is that I can workout for 364 days a year, but if I miss one single day, then the habit is broken and it takes the willpower necessary to move a fucking mountain to get back to the gym after that. It feels like I don't built habits no matter how many times I do it.
It's still necessary to rest, but the fear is legit.
Could be as simple as taking a day off training and just going on a long walk or doing chores around the house. It's a rest day where you use your free time to do something vs taking a day off where you do no real physical activity.
Like what the other person said. Stay active, but don't do any formal (or at least stressful) exercise. Gentle NEAT is better than being sedentary (unless you're severely ill or injured).
When I fall off my routine I lose a ton of progress. That first hundred K after a long rest absolutely sucks for me. I won't run on an injury, but I understand the fear of the pit.
110k is neurotic. Distance runners are often neurotic, they run for the runners high, they run as an antidepressant, they run to burn calories because they eat too much to deal with life stresses, they run to escape loneliness, they run to make themselves healthy so they'll be more attractive to potential mates, they run to get time away from their family, they run to replace other addictions they're running away from, I've experienced it all and I've seen it all.
Don't ignore pain, listen to it. If it hurt that's because you need to fix something. So think of what you have done that cause it. Did you change your habit? Why on this side and not the other? Did something different happened, not necessary in sport, but in your life?
Then try to change and see if you fixed the problem.