Just a few weeks ago I celebrating my decision to load up on FTSE 100 growth stock JD Sports Fashion (LSE: JD) in January.

I snapped up shares in the trainer and sportswear retailer at a 20% discount, after the board issued a profit warning following a disappointing Christmas trading period.

I’d been waiting for this opportunity for donkey’s years. Every time I checked, the JD Sports share price seemed to be leading the pack, and I felt I was missing out. This was my long-awaited shot at glory.

Why has it fallen out of fashion?

The danger with buying shares on bad news is that there could be worse to follow. When a momentum stock hits the wall, there’s no guarantee it will pick up the pace again.

But after a few ups and downs, JD looked well set. By September, I was up almost 30% and going for gold. I expected further gains as the cost-of-living crisis eased and consumers had more money to spend.

JD Sports is expanding in the US via the recent acquisition of Hibbett, with 700 new stores planned in four years. Once the presidential election was out of the way, I anticipated more excitement stateside too.

I’m not celebrating today. The JD share price peaked at 159.7p on 17 September. Today, it’s down to 116.75p. That’s a peak-to-trough drop of 26.9%, wiping out all my early paper gains.

The shares are down 16.25% over 12 months and 49.13% over three years. JD is no longer leading the pack, but trailing it.

The group partners with major international brands, notably Adidas and Nike. Unfortunately, Nike has had a dismal run. Its stock hit a four-year low in the summer as sales slumped, and that dragged JD down too.

Is this former FTSE 100 darling still worth buying?

On 2 October, JD posted a 2% increase half-year profit to £405.6m, beating expectations in a “challenging and volatile market“. It didn’t help. Worse followed.

In her Budget on 30 October, Chancellor Rachel Reeves hiked employers’ national insurance contributions, slashed the thresholds at which they pay it, and lifted the minimum wage by an inflation-busting 6.7%.

This will hit JD hard from April as it’s the UK’s 19th biggest private sector employer with almost 80,000 staff, many on the minimum wage. Chairman Andrew Higginson, who also chairs the British Retail Consortium, went on the attack saying the increases were “too much to bear”.

But JD will have to bear it. And so will I. I’ve waited too long to buy this stock, and I’m not going to sell after one setback. The question is whether I buy more.

Today, JD looks good value trading at 9.64 times earnings. It looks even better value judging by a price-to-sales revenue ratio of just 0.6. That suggests I’d pay just 60p for each £1 of sales JD makes.

If I didn’t hold JD, I’d leap on this chance. But I have a pretty big stake so I’ll sit tight and wait for better days. I think they’ll come, given time.