One more before I go....
I would strongly consider adding liver support. Whatever is going on, plus the meds, will be hard on the liver. My favorite support is this one: http://www.iherb.com/Country-Life-Gl...0-Tablets/1670
There is usually not high calcium with most tick diseases, however, there is an oblique reference to calcium balance at the end of the first paragraph here: books.google.com/books?id=Jpg1ysgVn-AC&pg=PA151&lpg=PA151&dq=babesia+calcium&source=bl &ots=li0-pZo_fs&sig=V5Q8f3L_YxknU6xSm4KfPOE6IRU&hl=en&sa=X& ei=b_8XUaCSCYqniAL9loG4BQ&ved=0CGMQ6AEwCQ#v=onepag e&q=babesia calcium&f=false
We usually don't have babesia on our minds when we think of tick disease. The problem with babesia, is that it doesn't respond to doxy. Typically, on the list, imidocarb is used when babesia is suspected, as it will also hit the ehrlichias, though I don't know what it will do to the spotted fevers.
If this were my dog, I would call Protatek Labs, who specializes in these things, and they can tell you what to test for. The lab director, Cynthia Holland, is wonderful, I have talked to her on a couple of occassions when I called about my dog. Most of us on the list, send in our own bloodwork to that lab. http://www.protatek.com/reflab/index.html