The fungus in dreams is the symbol of negative aspects in your waking life. Perhaps the dream is trying to show that there are certain thing you are doing in the wrong way. Make sure you find the solution for the problems you have, otherwise the negative emotions will get unmanageable.
Dream dictionary: Fungus dream meanings
To dream that you have an infection means that there is something in your life that makes you feel ill mentally or physically. Sometimes the fungus can indicate the poisonous thoughts the dreamer has which make him feel bad.
(See Herpes)
Disease, difficulties and problems. Nervousness and anxieties.
…(Fungus | Ringworm | Tetter) Suffering from herpes, or ringworm, or tetter in a dream means stinginess, or having resources to repay one’s debts and concealing such knowledge from the lenders and being afraid of their asking for their money….