Hi Lark,

I completely agree with mrsjoggers, your self awareness sounds like a great start to working on things
You recognise and acknowledge some screw up's, which might be avoidable as you know that theoretically you CAN handle the job.
So.........I'd say that it might be good to take one screw up, as a start, and list every reason you can think of that may have made it happen and do a little action planning as to what things might help reducing the chances of that happening in the future.........e.g. were you feeling under pressure or distracted in comparing yourself to how others might do it, so could you (at the very beginning) take deep breaths/block out anyone else and focus on what YOU are doing; were you lacking confidence at that time so could you firmly remind yourself of your abilities; were you feeling unprepared anyway so could you talk over to yourself what you were going to be doing or check in with someone; were you feeling overwhelmed so could you abbreviate the task or postpone/deflect it slightly until..........; were you just feeling disillusioned so could you focus on the reward/sense of achievement you'd be entitled to feel from "getting stuck into" the task; were you feeling down/like an "outsider" compared to your colleagues so could working on developing those relationships help you feel more "comfortable"/confident...................????
But just remember you may be focusing much more on your weaknesses than on others e.g. your colleagues (who you're comparing yourself to) probably have a lot more weaknesses than you're recognising........and your strengths/actual achievements........are you really recognising and giving yourself REAL credit for those??
Might improve your confidence and help your focus............
All this assuming that it's not the actual job which you might not like that much/or just that it's not the right job for you???
But your sister........her career...........personally I say that it's so much more important who you are/the kind of person you are, and how you treat others, than any position in the job market. For me that kind of fades into insignificance compared with...........
So.........kind of saying..........recognise your personal qualities too...........and even if it's about showing honesty (like you have here!!!), having shown consideration to someone last week/month, being someone who tries (which your thread massively emphasises!!!)............and try to feel good about those things, they matter immensely

Alison