Leicester raised a number eyebrows when they paid £1million to then non-league side Fleetwood for Vardy in 2012.
The 27-year-old striker struggled in his first year with just four goals, but Foxes boss Nigel Pearson stood by him and he has now rewarded him by hitting double figures already.
Vardy has played a major part in Leciester's push for promotion and they are firmly on course for the Premier League as they currently sit eight points clear at the top of the table.
"Last season it wasn't going my way and you let doubts creep into your head," he told the Leicester Mercury.
"I wasn't impressed with my performances and, when you are not playing well, you do get doubts in your mind. I let those doubts take over.
"There was a point last season when I decided to have a little chat with (assistant manager) Craig Shakespeare. The staff have been great and they told me they believed in me and that wasn't going to change.
"They kept telling me that I could make the jump and it was always nice to hear.
"They believe I can kick on if we go up and, hopefully, that will happen and I will be able to go up another gear.
"Hopefully we can get into the Premier League and then we will see what happens.
"I am not letting anything get in my head again.
"I just have to keep it going now. I have to keep working on the training field and transfer it to the pitch. Now I will get back into training and prepare for Barnsley."