❤ Why am I so USELESS!

Work was fine when I'm back to work after my holiday.
But today was terrible, as I make a grave mistakes in work, which is generating Letter of Demand for Starhub & get say bu my admin officer.
I know sometimes her attitude & talking is very straight, but I've already apologise to her, but seems like it's always my fault for not doing correctly.
Now I'm like handling admin all alone, without anyone helping, so I'm really very stress & tired about it, but I don't blame anyone at all, all I want to do is to do things correctly, without any wrongs, but it's like, hais.
I'm trying to hold my tears, but during lunch time, I break into tears, is like Idk what to do, I know I'm useless, only know how to cry & not trying to figure it out, but then I really don't know what can I do, as I'm still new in this line.
Idk when am I always so careless, why I always can't get things done well.
Sometimes, I really feel like giving up, but I know that I can't afford to give up as I need this job & also I cannot let Joanne Ahjiejie down, because is she who introduce me into this company.
I'm always telling myself that I must get everything done prefecting & not having any mistakes, but at times, it's really hard to do so, as it's really not easy.
Actually Mummy doesn't know what's my job scope like, that's why she'll always blame me when I tell her what happen everyday in work, & thats makes me feel useless, helpless.