Agree with others, stress fractures tend not to show on an x-ray. Have you been back to the sports physio since your initial appointment? You don't mention any follow up appointments. I'd suggest you need to go back. Also, if you keep doing little bits and it keeps hurting, then surely that is telling you something? STOP!!!
Depending on where the fracture is, depends on whether you should even be cycling. I've had friends with stress fractures, one was permitted to cycle, the other wasn't. Can you swim? That's not weight bearing. If you're not a swimmer, then you're stuck with total rest. Maybe do the jobs that you've been meaning to do for months?
Ultimately, few of us are qualified to know what it is. Even those who are shouldn't diagnose without seeing you. You need to go and see someone qualified to comment and in the meantime, stop flipping training on it if it's hurting you!!!