The cold, not warming up enough, stress from the environment, bad sleep, dehydrated, arm is tired from the week, slow gun....all these things could contribute.
If you don't have pain or discomfort you are probably fine. I agree with Ted in terms of taking it easy this week but not stopping all together. Do your recovery work (stretching, bands, wrist weights....whatever you are doing as part of your program) as normal this next week.
Total rest is not ideal recovery.