Well, yeah, but having a conscience only goes so far because your conscience has to be selective enough not to trigger on honest mistakes and mess-ups, which is what the OP's situation was.
If you feel totally guilty about every mistake, then you're probably being bothered by false guilt.
The function of guilt is to kick in when you've done something wrong, stick around until you fix it and figure out why you did it and institute some measures that'll help you not do it again; and then to go away. If it doesn't go away, or if it starts up when you haven't done anything actually wrong, then you've got an over-active conscience.
Best cure: Tell yourself, "I'm feeling guilty over something I shouldn't be feeling guilty about. It was an honest mistake, and I can apologize, make a note of it in my list of "things not to do", and go on."
Of course this takes repeated applications before it starts to work.