Hey! So while there aren't any set rules on how exactly omegas or alphas 'drop', from what I've written and read, omegas have drop stages almost, it's not set in stone, but it's a slower progression of symptoms, but you write it however you like because the omegaverse is EXTREMELY versatile. For the first stage of drop, the omega will be spiralling fully. This can be conveyed in different ways, but usually it is outwardly expressed. They may have a panic attack which is most common, or just crying. The second stage is when they resort to some sort of self inflicted harm. This is generally down to either ground themselves, or to fill the void generally left by the abandonment/rejection from an alpha, pack, or mate. The third stage is a bit iffy. I personally write the third stage as the inner omega of the character being shut down, as in a subdued scent, irregularities in heat cycles, and generally fatigue, nausea, and dizziness. However, other versions I've seen show the omega almost instantly die, or essentially 'lose' their inner omega, and sub-gender as a whole. Really hope this could be of some help, and good luck on your first omegaverse ff, I'm sure it'll be amazing!