Brief Answer:
Causes can be many, usually benign.

Detailed Answer:
I read your question carefully and I understand your concern.

Causes of dizziness can be many, most of them are benign, at times it is transitory and it passes without a cause being found.

One cause to be considered with that pressure feeling would be sinusitis. But usually has other signs like running nose and nasal congestion, headache, low grade fever so if none of those present unlikely.

Ear related issues at times cause dizziness but usually with sensation of vertigo, sensation of spinning movement, often exacerbated by change of head position, if those features are lacking unlikely as well.

Changes related to anemia or metabolic changes must also be excluded, for that some fairly routine inexpensive blood tests are necessary like blood count, blood sugar, liver and kidney function tests, electrolytes, thyroid function, vitamin B12 levels.

Blood pressure and heart rhythm also must be checked. Unlikely to be the cause at your young age but there are exceptions, so measurements of blood pressure at rest is recommended as well as an ECG.

Last possible cause, if the rest comes back negative and symptoms persist, brain related causes which I see you already discussed one week ago with a colleague might be excluded by brain imaging, preferably MRI.

I notice that perhaps the list came out a little long, hopefully I am not scaring or confusing you. Most probable result at your age is that it's nothing serious and it's more related to stress, I am suggesting all these causes more as a precaution to be checked in case symptoms persist.

I remain at your disposal for further question.

---