The Bachelorette star and interior designer recently joined the show for a project in Oklahoma, helping to design a children's room as the team built a new house for the Skaggs family.
Speaking to ET Online, she said: "It changed me a little bit. It sounds cheesy and it sounds cliché, but I used to be one of those people who drove to work and let the sun shine through my window and get a little tear in my eye and be grateful for life.
"After the past year-and-a-half, I have seen so much and travelled so much, it has been a roller coaster. I became a little numb to the things that made me so grateful [before]. I am a little bit embarrassed to say it."
She continued to say that her experience on the show had been "positive" for her, adding: "I came back and I was like the old Jill. The Jill who used to tear up over sentimental commercials, the Jill that gets excited to lend a hand and smiles at the person who is bagging your groceries at the store."
Extreme Makeover: Home Edition airs this Sunday at 8pm on ABC.
> Jillian Harris: 'Home Makeover' is inspiring'