Can Zoloft (sertraline) and lamictal cause candidiasis (fungus) on tongue? Tried antibiotics 3 times before, but it still wont go away! What can the causes be?

No. Zoloft (sertraline) and Lamictal do not cause thrush-candidiasis. The treatment for oral candidiasis is an antifungal. Maybe you don't have candidiasis and it is a chemical or thermal burn? It could also be hairy leukoplakia, premalignant leukoplakia, lichen planus or reactive glossitis... Ask a dentist.
It could be the. 3 tiimes you used antibiotics. Antibiotics kill bacteria which allows fungi to flourish.