It could also just be too much sugar.... veggies have Sugar too and when you take the fiber away by juicing some people react to the hight level of sugars that are left. I would recommend to eat the veggies raw or steamed. For becoming more alkaline try an algae product like E3 Live or an unsweetened greens powder. Both of those will help in two ways, one is that they will pull the toxins and heavy metals out that can cause candida in the first place and they will also act as eating an extra 4-6 servings of veggies.
Keep your blood Sugar balanced by eating protein several times a day, take supporting suppliments like chromium, zinc, vit e, magnesium and the B's.Start on some high quality cod liver oil the vit.A and D will help. Then get your hands on a super stong probiotic. I like Bio-k and Natren brands, I found them both effective.