Viral infections and stress can cause multiple hormonal issues, from testosterone to insulin to thyroid, out of which a lot will be skipped or only a partial picture will be given during average blood test (i.e. just total test or TSH).
Unfortunately, most docs will just skimp over the results or tests to be done, so the things like "I'm tired a lot" just get handwaved away. (Un)Fortunately, a lot of friends brought their blood tests results to me since I've spent quite a long time biohacking, and nearly always it was the same: the doctor didnt do a full panel but just a partial one, said something is okay or mid, when it turned out that a full panel indicated a much bigger issue. Hell, one of them would even fall unconscious nearly once a month and multiple doctors said "it's just stress" when it turned out the person was hypoglycemic and their sugar and blood pressure would crash.