04/08/2013 at 09:55 AM EDT
For Miranda Lambert
, being Sunday night's big winner at the 48th annual Academy of Country Music Awards
caused her a major attitude adjustment.
Besides, she admits, she was really rooting for somebody else.
"I'm a pessimist," Lambert, 29, told PEOPLE after the show, "so I'm always like, when is the other shoe going to drop? It's over – my primetime is done. But your peers vote for you and believe in you, especially as a songwriter."
"I mean – I really, truly was rooting for Carrie [Underwood]
. She really, truly is an inspiration to me as a vocalist, and I love her and I really wanted her to win tonight."
Continuing her praise of Underwood, Lambert said, "She did win some Grammys
, so hopefully that made up for it, but she is just so good. She can sing any one of us under the table. Anytime I see her perform, it's like, 'She needs to be the female vocalist!' "
In all, Lambert won four awards, more than any other nominee on Sunday. Her "Over You" was named single record and song of the year, earning her awards as the song's performer and co-writer – with husband Blake Shelton
. She also was named top female vocalist for the fourth consecutive year. (For a complete list of winners, click here
"My tough girl image is out the window," the Texas artist, who shed tears during the course of the evening, told PEOPLE. "You just dream of it your whole life and you get there and you're thrilled and it keeps happening."
Then again, she conceded, "The whole night was emotional – everybody was truly happy for everybody. I looked around and people were shaking hands and hugging, every artist in the category was proud of the other ones.
"When people say country music is a family, they don't understand what we're saying. But if you watch the show tonight, I think the point came across pretty well that we root for each other."