My worst fears

Well friends,
I haven't posted in a long time. I've been working steadily on my MBS.
This week I was hospitalized for vision changes in my left eye following cataract surgery June 9. After multiple consults and tests, the diagnosis is essentially a stroke to the optic nerve. There is a very low probability of giant cell arteritis for which I am having a temporal artery biopsy tomorrow morning to completely rule that out. In the meantime I am on steroids until that happens. The steroids of course have decreased all other aches and pains ...for now. My driving is not limited and in spite of this, my vision is near 20/20 in that eye though peripheral vision is quite badly affected in spots. Needless to say, it has been a difficult week. With my history of migraines and a balance disorder for which they can do NOTHING, I have my hands full applying what I've learned for 2+ years with MBS. I've been in flight or fright for too long this past year, largely financial and feel this is the result of it. Even though I have done my best with Schubiner's program, Dan Buglio, and Nichole Sachs and read many many books. So now I am trying to stay calm but this was not what I expected to hear at all.
If the biopsy is negative tomorrow, the steroids will be tapered off. This has completely rocked my world. Going forward how will I know when to take action about symptoms and when to try to settle myself and not catastrophize??