I treated my daughter (nonverbal, soft autism at 2 due to candida) with nystatin oral powder and diet. I don't think the tablets are as effective as the powder. One year later she is almost at her peer level in speech, re-diagnosed as phonological only, no autism. Now I know the underlying issue for us both is really my silver Amalgams and the mercury she inherited from me. If you just can't get rid of your candida no matter what, I would suspect heavy metals.
If you are in the US, you can get nystatin powder legally from a Canadian company fludan.com. It does take 3-4 weeks to get it due to customs clearance, but it is reasonably priced - costs me $140 total including shipping for 500MU quantity and this lasts me about 4 months.
Dose 1/8 teaspoon 4 times a day, mix in water. Good luck!