Changing taste buds and dragon breath

So lately after meals my taste buds are changing and my mouth feels real warm and nasty.  Reminds me of the feeling I used to get when SAD occasionally, but back then it would also be accompanied by really foul breath (at least I don't have to deal with that part).  I don't remember my taste buds changing because of it back then, but I am a lot more in touch with that kind of thing now then I was so who knows.  

It's crazy I can be drinking my filtered water from a 1 liter glass bottle before I eat and the water will taste unbelievably clear and refreshing.  Then I'll eat a meal and before I can finish I get that change in my mouth, which is actually making it hard to finish my meals now too.  The more I eat the worse it gets.  Then, when I'm done I can even drink from the same bottle of water and it tastes so undesirable to me and dirty.

Any ideas what could be causing this?  It all seemed to start about a week ago when I started eating a lot of watermelon.  But I really don't know if that has anything to do with or not.  Even though it seemed to start with the melon, it even happens with bananas and datorade now too.