I presume you have seen this topic:
And here you will find more information:
Optic neuritis is often, but not always, a precursor of MS, but if you have the lesions as well, it seems a certainty: neurologists are wary of giving a diagnosis too soon for obvious implications of medical and life insurance.
With your history of a mild heart attack when you were still only in your forties and the adult onset diabetes, it seems very likely that there is a CPn component. David's regime will not hurt you if you don't have MS: he has used it himself for heart problems and many people use doxycycline for reasons as diverse as acne and malarial prophylaxis for long periods.
If you wait until you have another exacerbation just to make sure you have MS you are letting time pass which might be spent on making yourself better. I had my first MS symptom when I was 24 but then I went for nearly five years before anther attack. When it was finally becoming progressive, attacks were coming every few months, then they stopped and it was just a process of continual deterioration until I started antibiotics, since when it has been continual improvement. Some people never have exacerbations: it is just continual deterioration from the start.
If you want to discuss this with your neurologist, take this PDF file:
It is more compressed and easily readable than printing out the whole of the site. Many neurologists are totally against this, because they think they have a propriatorial attachment to MS as an auto-immune disease. My neurologist is a case in point, which is why I haven't seen him for three years. However, you don't need a neurologist to prescribe antibiotics: many GPs will do that as the evidence becomes more pressing. Are you in the US or the UK? If the latter, you have the option of actually making an appointment with David. He doesn't charge. You can write to him from anywhere, though. Address at the bottom of the page one of the pdf.