Even after hearing from Omeluum that transformation isn't imminent, I would still be prioritizing getting the alien worm out of my head over everything else.
Also, if their plan is to say "Hurry, hurry, hurry!" and then quickly 180 into "Everything's fine, probably." then that's a huge letdown as far as storytelling. They've taken away my character's primary motivation 5-10% into the game.
I think your response would depend highly on what type of character you are playing. Astarion hints in early conversation that he wants to harness it's power rather than get rid of it, and if I recall correctly you can agree with him.
