The Leinster flyer missed the opening three matches of the tour because of a chest infection and fatigue after playing 30 matches in a season that netted him a Grand Slam with Ireland and a Heineken Cup winners' medal with his club.
But after arriving in South Africa he was told to take a break and was worried that he might get left behind in the race for a Test spot. It was then he asked for advice from his Dublin-based sports psychologist Enda McNulty.
And now Fitzgerald has been given his chance to shine in Pretoria this weekend after being called into the side to replace Ugo Monye on the left wing.
"When I wasn't playing and had time to myself, things did crop into my mind but, thankfully, I got some really good advice. I've got a very good support structure in terms of family and guys I can talk to, such as Enda," said Fitzgerald.
"He's great for off-loading things that are weighing on my mind and he said to stay positive and just keep plugging away. That has really helped.
"It was difficult because you're such a long way away from home and you can feel isolated when things don't go your way.
But I've got a lot of support from players in the squad and people back at home and they help take the brunt of the pain away when things aren't going well.
"My family will come out to South Africa this week so it will be nice for them to catch up with them and be close to me in such an important moment in my career. They have always been there for me and I'm just delighted to be given the opportunity."
Included among the Fitzgerald clan supporting 21-year-old Luke will be his father, Des, who played for the Lions against a rest of the World XV in Cardiff in 1986.