Hi Pythagorean,
Are you still getting sick quite often? If so, you might be reacting to local toxins in the air, water, foods, or hard goods. They can cause digestive system upset, and/or other symptoms. They can also make allergies worse, but of course so could exposure to a new type of pollen.
My medical past is not as visible as yours is, but when I must mention it I find that the way I present it has a huge impact on how I am viewed.
For instance, if I dismiss it with a straightforward comment, in a tone which communicates that I do not need to concern myself with it anymore...