Welcome to the forum! I'am fairly new here myself, and I've learned quite a bit. Different regimes for controlling the yeastie beastie work for different people, and can take weeks, months, or years.
The diet is simple enough in concept, but sometimes difficult in practice. It means for the first few weeks giving up all sugars (most fruits are forbidden, except lemons and grapefruits), carbohydrates (no breads, though unleavened breads can be worked back in later, if you're not sensitive, and no starchy foods),just eating fresh leafy greens and lean, Antibiotic
and hormone free meats (red meats only once a week), and nod fried foods. After a month or so, depending on your progress, you can start slowly working foods back into your diet. You will most certainly deal with the yeast die-off reaction (the yeast releases toxins into your body as they die) as most folks here have, but there are ways to deal with it, such as Colon Cleanses
(Psyllum and Bentomite shakes, for example), liver cleanses, detox baths/showers, and various detox aids, like milk thistle.
You may also have to spend some time to determine if you have leaky gut, and if you do, you will have to work on a plan to heal your gut. You and your naturopath may have to explore whether or not you have parasite
issues as well.
As for Threelac (or Fivelac), while I have no personal experiance with it,it seems to have a very mixed record of success here. You might want to stay away from that for the time being, and go with other products, or the proven natural anti-fungals. Searching the group here will bring up a wide variety that seem to have good track records, and don't require multiple levels of products (read high expense).
You most certainly will be looking at buying or making probiotics to help restore your internal flora balance, and there are many homemade probiotics, like kefir and cabbage juice, that you can do on your own for a relatively small cost.
So take some time to look over the forum, read what has worked (and not worked) for people here as well as the links to articles and products that will help educate you on what you are dealing with and how to bring it under control.
So I wish you luck, and success in beating this thing! :-)
But bear in mind that what works for some people, does not always work for another. You will have to spend some time experimenting to find out what is the best way for you.