bev

I have a question. I had an investigatory meeting with my line manager as I left my shift 1/2 hour early. He had me to sign a statement that he had made during the meeting.He has today issued me with a letter of concern. When he handed it to me he told me straight away I couldnt appeal it ? The letter was not on formal company letterhead and he has signed but he has not asked me to sign? I have not informed my employer yet but I am pregnant and left early due to sickness.