Re: Gingivitis?/Candida? or im crazy???
The kind of medications you had to take could cause dry mouth or more specifically - deficient production of saliva. Saliva is there to constantly keep your mouth and gum moisturised and to clean your teeth, washing away the food debris. This obviously makes it a very important fluid, and so by not producing it your oral flora is threatened, so that is probably one of the reasons you got the irritated/inflamed gum. You need a good diet of natural foods to maintain good overall and oral health.
Overusing mouthwashes and brushing too often is not a good idea, even if it seems to help at the time, you should reduce it now. These products contain a lot of harmful ingredients and what is most important is the technique of cleaning, not the frequency of usage. Oral irrigators help a lot if your gum is more than mildly inflamed.
I can't really comment on your other problems, but there are a lot of pictures online of oral thrush, as well as the symptoms, so compare and see if that's what you have. You could also use a tongue cleaner or even just your brush to see if the stains will be removed with cleaning, if you're not convinced it's oral thrush. Mouthwashes could stain the tongue, as well as the teeth if it contains chlorhexidine, but whatever mouthwash it is, don't use it more than once per day.