Yes a diet high in carbs can be a cause for opportunistic candida infection. The coating on the tongue could also be candida so linked in.

However, What you are describing sounds more than simply eating a lot of sugar in the past, and stopping it now.

The health food shops are likely to suggest pro-biotic type supplements as a way of getting good bacteria back to the levels you want them at.

As far as supplements go I am a fan of kids supplements as these are normally way below the 100% RDA that a lot of adult supplements are at. This normally means they can be redly absorbed and do not lead to stomach disturbance.

I am going to make a suggestion that I know you have had in one of the other threads. This sounds a bit more than just diet related, and you may well benefit from popping off to see your GP. It may be nothing, it may be coincidental, but it could be more, and you could do with having it checked out. I hope you have a good relationship with your GP and that he does not simply fob you off saying its this fad diet you are on. As that is neither helpful for you or the situation!