Linda, I don't really understand why this would be, but I noticed that my condition during a week of treatment tended to remain fairly satble in terms of not a lot of new symptoms but I often found my symptoms progressed and worsened on the weekend in between treatment! So you aren't alone in this. The main thing to realize, I think, is radiation works it's wonders and it's damage long after you are out from under the mask, so really your symptoms can get worse at any time.
If half your tongue is white that might be thrush, although when you get mucositis there also is a wierd whitish layer of stuff that covers your tongue. You should check it out with someone to be sure it isn't thrush because if it is, it will need medication to go away.
I lost my taste after about a week of radiation--that doesn't take long for many folks--seems like it's one of the earlier symptoms. Don't worry, it will come back eventually......hang in there!
Nelie