Neymar feels he is facing the most difficult time of his career as the Brazil star battles to prove his fitness before the World Cup.
The 26-year-old has returned to training at Paris Saint-Germain after surgery on a broken metatarsal suffered at the end of February.
He was named in Tite's squad for Russia 2018 as expected this week and all eyes will be on Brazil's first pre-World Cup friendly against Croatia on June 3.
"This is a difficult time, one of the most difficult that I have faced," Neymar told Jornal Nacional.
"I know that everyone is nervous, but nobody is more anxious than me to go back and nobody is more afraid than me."
Neymar stated these anxieties played a part in him spending the majority of his rehabilitation surrounded by family and friends in Brazil.
He said: "Everyone was always cheery and it became the norm. This made me happy and helped me with the day-to-day work and the stress.
"Millions of things go through my head. I'm scared."
Brazil begin their Group E campaign against Switzerland on June 17 and will also take on Costa Rica and Serbia in the round-robin phase.