Welcome to NeuroTalk....

There are two simple things that if you are having problems with, can be fixed easily and inexpensively.

I'd get tested for B12 and Vit D right away. Recommendations are for people 50 and over in US to take a B12 supplement anyway. But low B12 is very common, and getting tested a good idea. Don't accept "normal" or "fine" from the doctor either, as lab ranges in US are low... You should be at 400 at least or preferrably higher. Low B12 has been implicated in Alzheimer's too.

Vit D also is necessary to keep your immune system working well. New guidelines are for at least 50 (US units).

If you are low in either... fixing them often helps with many issues.

I have a B12 thread here:
http://neurotalk.psychcentral.com/thread85103.html
Some drugs like metformin, hormones, and OTC acid blocking drugs as well as RX ones lead to low B12 levels.