The 22-year-old seemed set to play a pivotal role for the Red Devils' after an impressive start to the campaign but an ankle ligament problem curtailed his involvement and he did not start a Premier League match after October.
"It has been a nightmare at times but I am only 22 and have around 15 years ahead of me yet. I just hope I have got it all over and done with now," he told the Manchester Evening News.
"There were times during the season when I thought I was the unluckiest footballer in the world.
"From a great start it became the hardest season of my life but it has made me mentally stronger.
"I've always had to cope with disappointments in my career. I had two injuries over the years (undergoing shoulder surgery and having a knee problem in loan spells at Leicester and Watford respectively) but I got through them."