Learn German: Die Sitzung dauerte gefühlt ewig. - The meeting felt like it lasted forever.

It is the past participle of fühlen, but here it acts as an adverb. In conversational German, gefühlt is frequently used this way to express a subjective impression. Instead of building a clunky subclause, you just drop gefühlt right in front of the adjective to mean that it felt that way.

Why use die Sitzung instead of das Treffen for the meeting?

Die Sitzung specifically refers to a formal, seated gathering like a board meeting, committee session, or council meeting. Das Treffen is a broader word that often implies a casual get-together, while die Besprechung is your standard workplace meeting.

Could I translate the sentence using a longer phrase like Es fühlte sich an, als ob...?

Yes, you could say Es fühlte sich an, als ob die Sitzung ewig dauerte, which is grammatically correct. However, using gefühlt as an adverb is much more concise and is exactly how native speakers talk in everyday situations.

Can ewig be used for both literal eternity and exaggeration like in English?

Exactly. Just like in English, ewig literally means eternal or endless, but it is constantly used in everyday speech to dramatically exaggerate how long something takes.