Is it normal that masturbating doesn't phase me anymore?

I have been masturbating since I was little. I used to do it all the time, but it's really been an on and off thing through the years. I feel like I've tried everything and ever since I discovered the running bathtub water method, I don't find anything as pleasurable as that. Most of the time I don't even feel like doing it, but I feel like every time I take a shower I have to. I've done it so much that it doesn't seem to phase me at all anymore. I don't want to do it as much, but I can't help it; Don't get me wrong, it's nice and everything. But it's so old and very boring now. Is this normal? Is there anything I can do to make it better?