Your fears make sense, Scarlet...and I'm pleased that you're sharing them here.
L's return to work is bound to be something of a work in progress at this stage, and I bet she's trying to figure this out too.

Unfortunately we can't speculate on why she might not have read your whole message.
It's possible she thought she would offer you reassurance by saying that you haven't been forgotten, and that backfired.

Responding to email is more cerebral, I think, whilst responding to an emergency/crisis message is more immediate.

You can't know what is realistic until you've spoken with her, but it's an important conversation to have.