I hope you have recovered. I am sorry I missed your post on my whiteboard.
My husband used to get really bad throat infections every winter. He had that funny coating on his tongue, too.
He started eating yogurt (Plain with live cultures). He hasn't had a throat infection since then.
You could also try acidophilus capsules that you buy at a health food store or drug store if you don't like yogurt without flavoring.
The acidophilus is "good" bacteria that help your immune system stay strong.