Do you still have any 10 mg pills? You could drop to the 10, and then cut them in half to make 5 mg. But jut don't go to fast. you will likely noticed a difference between the 15 and 5.

I totally understand why you want to get off it. Did you talk to your pdoc? I know my own pdoc was not helpful for this. Pharmacists are also another good place to ask how to taper off, if you don't want to ask your pdoc.