"wrote the wrong amount of medicine on my records"

I took my shelf to a&e, the with a swollen leg I thought I had a dvt, as I had one before, the care seemed good ,but the doctor wrote the wrong information down on my medical records. he never asked me if I was pregnant but wrote on my medical records that I was and they were going to give me 2 injection of blood thinner, instead of one. this was worrying because I could have been given a bigger dose than I should have had.it was only when the nurse asked me and I told her I was not pregnant. she said she would complain. I was in a lot of pain and I put my trust in the doctor in a&e I feel let down because I could have had the wrong medicine. the lack of communication was very clear to see with my treatment.