I'm also using Interfase plus for Candida, but I'm not feeling crappy, but I'm also taking two other supplements, each to chelate lead, mercury and thallium:
1) Chelorex (1/3 dose)
2) Neuro-Antitox II w/apple cidar vinegar.

I'm trying to kill candida and do a removal of my heavy loads of metals at the same time, but I know atleast the chelorex will bind the heavy metals pretty good, I have used it before.

Check out the chelorex product, its all natural. It slows you down when you take it, but when you stop and give your body a break say after a number of days of taking it, you feel better then when you started your last batch of chelation. I have little experience with EDTA, sorry.

I'd check out this article, on your journey towards beating candida:

[Wont let me typ links, so google "gestaltreality", "resistent starch" and "bio hack of the decade" and you will pull up a great candida article]

I recommend the reistant starch. It helps me sleep. I either do it or the fibre to feed my good critters, and of course i take my probiotics-dr mercola. I treated for 6.5 weeks, eased up for about 10 days to take some tests-just reiced dosages, did my organic acids tests, its shows up with a semi strong presence, but on other tests like stool OR IGA,IGE, IGG it didnt show up (the acids is the best test). So of course its the biofilms is the last to go. Also for attacking the biofilms, I'm taking Candex, nattokinase,and serrapetase(already in interfase plus). You could also try lufenuron.