Tam, more sunlight (real or faux) should not hurt anything that is going on, and may make it much easier for the medicos to see the rest of it clearly. If SAD is a reality for you, you'll want to do something about that as soon as you can, so that you can think most clearly about any other issues that may also be present.
Think of SAD lights not as one more cure for one more ill to diagnose and treat, but just as another necessary stay-well item.
And yes, SAD can intensify with age because it saps your best at a time when other aches and pains may make your best harder to achieve to begin with.
I wouldn't start with an expensive lightbox though, and if you look at the older thread you'll see many less-expensive approaches may of us took, plus the specs to look for when shopping for any full-spectrum lighting item. Just start by getting an inexpensive bulb for the place where you sit most.