If you look up die off through this forum you will see that it can range from varying symptoms. It’s hard to tell what is related to die off and what is a candida reaction, because they feel to be differing for every person. If you think it’s the sugar that has been the problem then I would just keep trying the candida diet and possibly slow down on the probiotics and just see how your body keeps reacting, but if your digestion is impaired from not taking them I would not stop them. You want to keep digesting food as normal as possible.
Also search the forums for oral thrush as die off and such. It always helped me to see at least one person with the same problem. It gave me some relief.
Hope this helps, sorry it’s not that great of an answer.