Brief Answer:
Thyroid

Detailed Answer:
I have noted your TSH result and overall medical condition.

You likely have a condition called 'Primary Acquired Subclinical/mild permanent hypothyroidism due to chronic autoimmune (Hashimoto's) thyroiditis'

What this long jargon simply means is that you have a mildly under active thyroid gland due to a common condition in women called Hashimoto's disease. The body's own defenses (which protect against infection), begin attacking your own thyroid cells causing variable degrees of destruction.
This process is not painful. The variable degree of damage results in mild under-activity in some versus complete loss of thyroid hormone production in others.

With your TSH being slightly above the upper limit of normal, it is not urgent to start treatment.

There is also one more diagnostic possibility called 'Recovery from Transient thyroiditis'. This is a temporary condition which often corrects itself without requiring any treatment.

When I see someone like you in my practice I do the following:

Check blood levels of Free T4 preferably on the same blood sample as the TSH. If this is not possible then another blood sample as close to the date of the TSH draw is desirable. This helps me ascertain if the condition can be labeled Mild versus Overt.

If many days have lapsed then I discuss all options with the patient and see if they wish to run tests now versus 6 weeks later.

So if there is no neck swelling ('goiter') and no strong family history of this condition then I generally recommend not starting any thyroid medication and waiting 6 weeks and then running the following tests:

CBC
CMP
TSH
Free T4
Thyroid auto antibodies = anti TPO (thyroid peroxidase) and anti Thyroglobulin antibodies

None of these tests require any fasting and can be done at anytime of the day.
If roughly 6 weeks from the day of the first TSH, the next set of labs show a similarly elevated TSH in the presence of positive thyroid auto antibodies (even one of the two is sufficient), then it is likely that this is a permanent condition.
Treatment with thyroid medication is worth considering.
However, there is evidence that in older individuals, mildly high TSH does not necessarily represent any abnormality.

If the 6 week lab results how normal TSH and negative auto antibodies then it is likely you were recovering from the temporary condition. In such a situation it is advisable to check TSH again in couple months to make sure it stays normal.

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