The Tigers came from behind twice to claim a 5-3 victory over their League One opponents, and book their place in the final for the first time in their history.
"There's a feeling of relief and being thrilled as well," Fryatt told the club's official website. "For this to have happened is almost unimaginable and emotionally draining. It will probably sink in properly tomorrow.
"At one point, it didn't feel like it was going to be our day. To turn it around and win a semi-final 5-3 is just crazy stuff and to say that we're in an FA Cup Final now is incredible and something I never thought I would say.
"I've certainly played better myself, but the whole occasion and playing at a magnificent stadium like Wembley makes this the biggest game of my career. Helping your team into an FA Cup Final makes it a very special day."
Hull will face Arsenal in the final at Wembley on May 17.