Strep can be tricky and not always obvious, if you are concerned, I would go get a culture. As Ducky said, that is the only way to really know for sure. Obvious symptoms (white spots, sore throat, etc.) are not always present when you have strep, believe it or not.
Another symptom of strep can be a headache.
Since you are on enbrel, I say go get it checked out before it gets worse.
Good luck.
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