The first one (or "j'ai l'impression de plonger dans une mer infestée de requins") could be understood better (maybe in a business environment). You can keep the beginning of the sentence and use "j'ai l'impression de me jeter dans la gueule du loup" zhich is the used expression if it is about being trapped in some way or in a dangerous or uncomfortable situation:
Hope it helps: (French native)
Corinne