I'd definitely say continue to get qualified medical opinions to make sure you are a) sure of the diagnosis and b) abreast of all current developments and possible treatments and clinical trials.
Getting your financial affairs in order is not a bad idea--not just when you know there is a serious medical condition, but in any circumstances, because none of us know when an accident or other sudden death could occur. So it would probably just be good to go ahead and handle that on general principle.
Now, from your post, I can't tell whether we're talking about, multiple sclerosis, ALS (Lou Gehrig's disease), or a less common condition--but you should probably also make provisions for long-term care. You may have been told a certain time frame, but at least in the case of ALS, certain people have been known to completely defy all expectations as to how long they were "supposed" to live (Stephen Hawking, for instance). There's no need for you to share what you've been diagnosed with, but that is a point to consider--doctors can provide probabilities but they cannot provide certainties.
You might also want to network with other people who have your specific diagnosis. Even the most uncommon disorders tend to have Internet communities.
But from a less pragmatic standpoint...it's not just important to get out of your life what you want, but to give all that you want to give, while you have the opportunity. You mentioned you are religious...it might not be a bad idea to look into service opportunities, while you are able to do so, maybe even multiple things you can do at various physical ability levels. Giving back is not only something that Christians and people of many other faiths are called to do--it can be good for you psychologically and physically too. It doesn't have to be on a "big" scale; such opportunities can exist both within the community and within your circle of friends and family.
Just my two cents.