Nausea sometimes occurs when people eat truffles. Unfortunately, some people have this reaction because there are also 5ht2a receptors in your intestines (and in the brain) where the psilocybin attaches itself to.
To prevent nausea from the truffles, it helps to take fresh ginger tea with them. Also swallowing them directly helps for some.
You could also try another substance. For instance 1cP-LSD.
Info: Microdosing with 1cP-LSD
Product: 1cP-Microdose