You should make sure you understand and accept the feedback given - remember that feedback is only ever a reflection of how other people see you; that in itself is important. Maybe it is personal, I don't know, but try to understand the criticism so you can do something about it.
I can see how this would affect your confidence and possibly your motivation too. Don't let it - it's important you step up now more than ever. Deliver high quality work on time - and do this consistently. Don't just do a good job, go the extra mile, overcompensate.
You might also want to speak to someone else you trust at work - ideally someone more senior who understands how things work in your particular firm.
I don't understand your last sentence - why wouldn't you check for errors before posting?
I should say I don't work in consulting (yet), but do have a few years' work experience (big 4 financial advisory) so hopefully that's helpful.