Gabriel was sidelined after suffering a broken metatarsal in a 0-0 draw at Crystal Palace on New Year's Eve.
He made his first start of 2018 in City's 2-1 Champions League defeat to Basel on Wednesday, scoring the opener for his first goal since November 18.
"When you're in the game, without wanting it, you end up thinking about the previous game where you got injured," said the Brazil international.
“You have a bit of fear. But, as you're playing more and more, you're going to get that fear away and play your football.
“I think I still played with some fear, and there's some movements when I still have some fear to got injured again.
“I know anything can happen, but I'm sure that the more you play, the easier that fear is going to go away."