The fly-half is currently recovering from a ruptured Achilles, which will keep him out of the entire Six Nations.
The 26-year-old BBC Radio Wales: "I wasn't really enjoying rugby, especially at the start of the Autumn Internationals I didn't really want to be on the field.
"After the Samoa game I saw Andy McCann, who's the sports psychologist with the squad, and from the first time I met him it was such a weight off my shoulders, just nice to speak to somebody. I'm not the sort of person who can easily ask for help, so just being able to speak to somebody and put things in perspective helped me a lot.
"I thought I turned things around quite well from the first two games to the second two games and I was really happy with the way things were going. Then obviously my injury happened but it's just one of those things."
Priestland hopes to be able to resume playing in April.