Laid low by a tenacious virus, he had just had to cancel his comeback to international athletics for the second time in two months. He felt lousy, listless - as low as he had been. Even his Mum was asking anxiously if he thought he would be able to run properly again.
Since then, however, the clouds have departed, health has been restored. And this weekend, Birmingham should feel the benefit.
It is three years since Robb propelled himself into world class 800 metres running with his performance in the AAA Championships and trials at the Alexander Stadium. He returns there today for a re-launch after an 18-month period in which his huge natural talents have been compromised by injury and illness.
Back then, the potential of a 20-year-old who had already won a silver medal at the World Student Games was obvious. But he was in danger of missing out on the Olympics until a characteristically bold run won him the 800m trials and gained him a qualifying time - and provided the championships with one of their most exhilarating moments.
In Barcelona he reached the final, finishing an honourable sixth. The bet his father Alex had laid in 1989 - worth pounds 100,000 if his son wins the 1996 1500m title - began to resemble one of the great wagers of our time.
Fourth place in the following year's World Championships, though it represented a huge disappointment to Robb himself, indicated that he was still on course for better things. But the upwardly mobile progress of this medical student ended in September 1993 when he began to experience pain in his knee.
For almost a year he continued to combine athletics with his studies, even though he was unable to run more than 200 metres without pain.
After seeing a succession of specialists, the best diagnosis he could get was that there was a wasting of the muscle beside his knee. Members of the Robb household thus became acquainted with the sight of the resident athlete exercising in the kitchen with a couple of bags of frozen peas draped over his foot for weights.
It did not do the knee any good but a chance encounter with a physiotherapist in the canteen of Sheffield's Northern General Hospital, where Robb was doing a placement to study psychiatry, led to the solution. The physiotherapist offered to look at his knee, and after the muscles around it had been strategically loosened, Robb found the pain had gone.
He was also advised to run with his pelvis tilted in a different position to avoid a tendency towards "sitting" on it which had exacerbated the problem.
That evening he went out for a run around the streets of Sheffield and, for the first time in 10 months, he ran without pain.
All went well with his winter training, and after a run-out for Liverpool Harriers in a British League meeting, where he ran an 800m in 1min 47sec, he was set to return to international competition in the Bupa road mile at Portsmouth. At which point he got the viral illness which was afflicting a number of his club-mates.
His return was rescheduled for the meeting at Gateshead on 2 July. At which point his illness recurred.
In order to concentrate on running this year, he had taken four months away from his medical studies. With awful predictability, Sod's Law had duly operated - and suddenly Robb was finding time hanging heavily.
"Get yourself a hobby," was the advice from his agent, Andy Norman. He suggested stamp collecting. He suggested antiques - after all, it had filled many an idle hour for one of his previous charges, Steve Ovett.
But antiques are not Curtis Robb. Instead, he toyed with the family piano - "it's out of tune so it sounds bad even if you are playing the right notes." All the more reason for his family to greet his return to fitness with enthusiasm.
Last week at Crystal Palace he took his first step back in an international 800m. "You try to tell yourself that you are out to win it," he said. "But it is a different thing when you have just put your foot on the line. It was a bit scary."
But the instincts held together well enough to gain him sixth place in a time - 1min 46.3sec - that was inside the world qualifying mark of 1:46.50. A job well done, in fact. "It was the best I had felt in two years," he said. He will be feeling even better if he can secure a place in Gothenburg this weekend.Reuse content