If I have hypothyroidism. Is it OK to consume hydrocortisone 5mg to help my body?

There are 23 diseases/conditions that Hydrocortisone interacts with, one of them is Hypothyroidism, the interaction is considered moderate meaning;

Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.

Moderate
Corticosteroids (applies to hydrocortisone) hypothyroidism
Moderate Potential Hazard, Moderate plausibility.

Corticosteroids may have enhanced effects in hypothyroidism due to decreased metabolism of these agents. Patients with hypothyroidism should be monitored more closely for excessive cortisol effects. Dosage adjustments may be required secondary to changes in their thyroid condition.

Source:
https://www.drugs.com/disease-interactions/hydrocortisone.html#Hypothyroidism

I recommend you speak to your Dr. in order to clarify any doubts/fears you may have.

Note: If the same Encocrinologist prescribed the Corticosteroid, he/she is aware of the potential interaction (s) and has outweighed that the benefits are greater than the risks involved and would not put you in harms way.