Hey there,
10 day waiting time isn't uncommon for management consulting firms to give feedback. Sometimes it can even go up to a month in worse circumstances. There may be many reasons (that have nothing to do with you or your performance) for why they haven't gotten back to you...
And even if you were to take it as a rejection and move on, then what happens if they come back to you with some great news! :-) Ultimately, your feedback will come... And if it's starting to take much longer than you'd like, then a gentle and professional follow-up would be completely reasonable
Wishing you all the best!