Not vocal enough for my job

I keep screwing up at work because my nerves keep getting the better of me.
If I wasn't so desperate to hold onto this job I would never have stayed on after the two weeks on the field.
My supervisor threw a huff from day one because she did not want someone on her team who had no peviously experience in this particular line of work.
Every client we visited was told " don't worry the other two girls they gave me have actually got experience"
I told my boyfriend and her mum said that she had heard that she was the type of person who had to be the best at everything and his sister said that the wannabees are often worse than the big wigs.

I really feel like the supervisor unintentionally makes me feel small. She targets me in the monthly meetings. It is subtle but I am not blind or stupid.
I admitted that after two weeks I was struggling with one client so I got threw extra days. This seemed to do the trick.

One lady left a clients safe open but I did not report her. She is horrid. She was ordering me to hurry up right in front of an elderly gentleman. I can't make a machine go faster ! And the poor man must have felt he was taking up too much of out time. I phoned her because she was half an hour late to one client and she snapped that I had interrupted her lunch and basically to sling my hook and wait. So I was going to be even further behind.

At the monthly meeting the supervisor was talking about a client who was uneasy about the number of different people who came to her home. The supervisor said that she trusts her team but glared at me directly and narrowed her eyes.
She then explained that our company had introduced occupational health check ins if anyone was interested. And the horrid one looked at me and said "is it for mental health"

Three. Sorry if I have typos. It's internet and I don't like to proof read incase I wimp out of posting it after I re-read it