Nurse working in UK

I am a 25 year old nurse working in the UK i qualified about 12 months ago, my very first shift as non supernumerary was a disaster, i felt like i couldnt cope as i didnt get time to check patients' blood pressures etc on time and i felt iike i was falling behind in general. Due to this i was put back on to supernumerary giving me learning time and after about 5 weeks time i was put back into the numbers and i forgot to continue fluids for a patient who was on what is called a "sliding scale" the patient was put on this due to his high blood sugar levels. I find this out the next day, the night nurse told me she had datixed me ( an incident report). Then in the afternoon i get pulled into the nurse mananger's office where they said that i will be put on an " capability action plan" meaning being supernumerary again but its more serious and my competencies will be retested and if i fail, it's the end of the road. Fast forward 3 months i pass all the competencies again, and pass the action plan. I am now one month of supernumerary, and i was super busy on a nigh shift and another nurse comes into my bay and says i should have reviewed all the patients' fluids earlier, i was aware and was gonna do them but didnt get the time, as i was in the middle of doing somethibg else.She basically tells me to call the doc and gets them reviewed. I had a feeling she was gonna tell the manager about this. And when i came back to work after a week's holiday was called in for a meeting with the chief nurse and my manager they said i am being transferred to a diff specialty bc on one of the night staff said i was struggling. I had no choice but to agree, and now i work in a theatre admissions suite (this is where i got transferred to) Previously i was working in a urology ward. I feel so incompetent as a nurse, am i just a dumb nurse and should i just quit ? I have lost all of my confidence and i honestly dont know what to do