Hi I have been absent from work 3 times over a period of 26 weeks first time was beginning of April 2 days with sickness and diarrhea 2nd time was end of April with a trapped nerve in my shoulder which I had a doctors,s sick note to cover this and was off 8 days 3 weeks ago I had my big toe nail removed and got an infection in it as a result of this 3 days had to be covered with a sick note as the rest had been covered by holidays. I returned to work on Friday and had my back to work interview which they said had gone to red so on Saturday I had to be in an investigation which there I was told there would be a disciplinary I work for aside and have been there nearly 3 year I have never had any warnings and I am really very worried of what's going to happen they said there is a pattern to when I'm off but I only work 17 hours anyway which is tues,fri and saturdays.

First question, where do you live?
Chances are slim however that your rights have been violated. Being out with a doctor's note does not guarantee a job unless company policy says it does, such as in some gov'ts and very large corporations. And generally there are no or far fewer rights for part time employees in such places anyway.

I once was fired for having bronchitis even with a doctor's note. I filed for UE and got it. And yes, they can fire you for being out too much - doctor's note or no doctor's note. But since you do have the doctor's note and were fired you will win your UE.