In my case, I tried for years without a wetsuit, but couldn't get beyond 25 yards. For me it isn't a case of how far before it is worth putting it on, but put it on or don't swim.
I am currently suffering from overtraing. My physio says it is partly caused by interuptions in my schedule caused by other problems. If I had continued steadily I might have been OK.
He says that if you stop completely the tissues heal in the wrong way. He advocates cutting rigth back on both frequency and intensity. Continued running will keep the tissues stretched.
In my words, I would suggest you cut right back, maybe to a gentle 20 minutes a day or alternate days for a couple of weeks and then slowly increase distance but not intensity. Increase intensity only when you are back up to a decent distance. The physio suggests that recovering runners should cut back on distance when they increase intensity, but that is hard advice to follow.