Cox, who represents the Battlefords, headed for Regina where Premier Brad Wall had called a caucus meeting.
But the excitement after that first meeting was cut short by a phone call Cox received while walking through the legislature's rotunda. It was his doctor's office telling him that he needed to go to the cancer clinic.
A lot of things went through his mind.
"I guess uncertainty probably is one thing," Cox recalled in an interview Wednesday. "Just wondering because I was new, didn't know what the diagnosis was at that time, what it was going to involve as far as time goes, and I didn't really know until we sat down with the specialist and he said this is what it is."
It was bone cancer. The finding was unexpected.
"I just had some discomfort in my rib cage basically that shouldn't have been there."
Cox, 61, lives on a small farm just outside Battleford with his wife of 34 1/2 years, Linda.
He'd been a real estate agent since 1974, but was inspired to make a career change by what he saw as Wall's vision for the province. Cox was a campaign manager with the Saskatchewan Party in 2003. He took a run at a seat in 2007, but lost to the NDP candidate by about 300 votes.
It was a tight race when he tried again last November.
"This time we were on pins and needles right to the end and we were very ecstatic. I had all my family there and it was great."
Then came the cancer diagnosis. Cox feared his political dream could be lost.
He needed to talk to the premier.
"It was fairly emotional," he said, taking a deep breath, a tear rolling down one cheek.
"And I know it didn't need to be. I'm not making a big deal of this, but we have such a tremendous premier and he's so compassionate and he just said do what you need to do."
Cox wondered should he step aside?
"I said (to the premier) where do we go with this? Is this something that I can carry on? And he said, 'Yes, you're not the first person that's had a disease and carried on as an MLA,'" he said.
"It relieved a lot of worries because ... I've been working to become an MLA for ... you might as well say eight years, and to have that dashed was going to be a tough thing to bear. And it was a great relief to hear that."
The bone cancer is in the earliest stage.
Cox has been getting chemotherapy since late November. He will be getting a stem cell transplant — probably in May — and expects to be in the hospital for two or three weeks.
That means he'll miss the end of the spring sitting, but it doesn't mean he's giving up his dream.
"No, not at all. I'm going to be here for a long time yet."