I also have the dreaded winter cold, and I know your fear of falling out of routine. If you are up for it, maybe just do the activity with less intensity, take more breaks, use less weight, do a shorter time.
I ran my usual route today, with a stuffy nose/head and sore throat. I just took it easier than usual, and took some walk breaks if I felt like it.
Everything in moderation and all that.
If you are feverish it's probably best to rest rather than exercise, cause the fever is already working your body more than it usually would.