They all go hand-in-hand. So here's what I'd do: Start with getting the amalgam fillings replaced (use homeopathic Hepar Calcarea Sulph. to help offset side-effects of the released mercury). Make sure to get tested for heavy metals (hair analysis seems to be the most recommended method for this) to find out which metals must be dealt with.
Also start diet modifications. Candida and Lyme both are "fed" by sugar, dairy, gluten (wheat/rye/barley/sometimes oats), and alcohol, so those would be things to try to minimize or eliminate altogether.
It might be good at this point to be tested for co-infections (Bartonella, Babesia, Mycoplasma, Anaplasma, Ehrlichia, etc.).
Next, work on getting the pathogen load (Lyme, Candida, etc.) down and learning how to detox to reduce herxing too hard from the die-off. Check out the thread for those New to Lyme at the top of the forum for detoxing ideas.
Also, it has been found that chelation therapies can help get the toxins from Lyme die-off out of the body easier/faster, and in some cases seems to improve Lyme/coinfection treatment effectiveness. There are many ways to chelate metals and Lyme/Candida toxins. For example, I just recently read about the use of homeopathic remedies made from metals (mercury, lead, cadmium, etc.) to chelate out these metals. There also is oral chelation using high-potency nutritional supplements and/or various herbs (cilantro, chlorella, etc.). And IV chelation (EDTA, etc.) is also helpful but is very strong and may not be tolerated at first.
Probiotics, antifungal medications, various herbs & supplements, and Homeopathic Candida Albicans, can help bring the Candida under control and keep it that way.
Please keep in mind the above is solely my opinion and is thus offered as education only; I am not a doctor. I recommend persuit of the above things be done only in consultation with a qualified Lyme-Literate medical professional who can monitor your efforts and make adjustments as needed to your protocol.
I hope this helps...take care,