During that time, the 25-year-old from Derby has become virtually the forgotten woman of local athletics.
Struck down first by mumps, in 2006, then by a stress fracture of the foot as she worked her way back to fitness, then by the skin disease impetigo, she was finally diagnosed with the chronic fatigue illness ME in 2008, causing her to write off the 2009 season.
It is a remarkable catalogue of misfortune – and she is still living with the last of those problems – but Stevens says it has left her more determined than ever to reach her potential as an athlete.
She was briefly ranked in the top five women in the country over 1500 metres indoors and was regularly pushing towards the top 10 overall before her problems began.
“I just want to be healthy and, in terms of running, I want to be back where I was, although, at the end of the day, it still has to be something I enjoy as well.”
A member at Derby AC since she was 12, Stevens was in good form approaching the 2006 national championships.
“I was in shape and hoping for a medal,” she said.
“And then I got mumps just before the nationals. It took a lot out of me but I got back to some sort of fitness and had a decent indoor season in 2007.
“I thought everything was wonderful for the summer but running was harder than it should have been.
“At first they thought I had mumps again, then I was tested for glandular fever. So I kept it low key that summer. I got some fitness back and then there was a pain in my foot.
“I had an injection but it still wasn't right and I ended up with it in plaster for six weeks.
“When I came back from that, I broke down again. I just wasn't strong enough. I would be awake for no more than an hour in the morning, then I'd fall asleep again for two hours.”
Consultant Bernard Norton, at Derby's Nuffield Hospital, where Stevens' mother works, and Dr Richard Budgett, the chief medical officer to the 2012 London Olympics, each finally diagnosed ME.
Budgett put Stevens on a strict recovery plan which insisted she did not try to run too quickly, too soon.
“I would do nothing faster than nine or 10 minute miles, then 10 second sprints and then have a full recovery,” said Stevens.
“Once it's diagnosed, you're not OK but you can start to learn about it properly to know when to have an easy day.
“It's now a case of managing it. They've told me it can last from 18 months to two-and-a-half years – but is that from when it's diagnosed, or from when you first feel ill? I don't really know how far into that time I am.
“People don't really understand it. You have terms like ‘yuppie flu' and people think you're just whingeing.
“You feel like you're always going on about it. They can offer you drugs to help but the prescribed ones are all on the banned list for athletes!”
Stevens, therefore, finds herself taking her return to competitive action step by step.
She has just come second in one of her favourite races, a three-kilometre event in a park in Armagh, Northern Ireland, and has, as she put it “scraped together a bit of an indoor season.”
Second in the Northern Indoor Championships 1500m, she was then sixth in the UK Indoor Championships and has run within seven seconds of her 1500m personal best, which stands at 4mins 21secs.
And since she is not 26 until June, she still has time on her side as a middle-distance runner.
The 2012 Olympics are in any half-decent athlete's mind but, her experience over the last three years have instilled a realism alongside the dreams.
“The Commonwealth Games this year would be a big ask,” she said.
“But it's very likely that it won't be someone who's going well now who goes to the Olympics – it'll be someone who's going well at that time.
“I'll be around 28 then and, if everything goes well, I could be around my peak.
“Right now, I have 12 weeks until the (outdoor) National Championships.
“But I'm taking each day as it comes. I want to get through my season healthy and get my times to somewhere like they should be.
“You can only be the best you can. If that's only northern champion, so be it.
“But I'm still here and I'll fight my own battles. I have the same enthusiasm and more – and so much determination.
“One day, I'll come through.”