Month, as an existing member of staff, I feel that the fire service are obligated to provide you a duty of care.
As you know what happened with me, it is never a problem with any of my complaints and making medical appointments, etc. Every wednesday morning I'm at the clinic for my anti_coag blood tests. My boss has said he trusts and expects me to deal with myself as a manager, which is good. I still have to get the job done though and never leave work/analysis requests incomplete before going home once it has been started. Especially on Friday, so it's a two one street. Hang in there bud, you'll be fine.
It may impact on your driving side in that you have to test every so often and be above a certain level. Are you usually outdoors or office-based. Has any senior officer spoken to you about your situation, or is it just 'other duties' for now?