"Worst experience ever"

i went to general hospital to give birth because my husband had said it was the best Leicester. Well, little did he know about the maternity unit. I gave birth November 2013 to my beautiful daughter. However, my labour was horrible. I was a first time mother give birth. I didn't have a clue what to expect. My waters broke Tuesday morning but there were no contraction so, i was sent home. By Wednesday morning they got stronger and i couldn't handle the pain. When i go into hospital i was given gas and air. However, this was not working. My legs were shaking so i asked for epidural. The midwife said there were no lounges available to administer the epidural. So then, my husband asked if i could have pethidine. The midwife then replied it can stop the baby from breathing. So we both said no straight away. The only option i had was the birthing pool, i was screaming my head off with the pain. I gave birth to my daughter. I then went on the bed and the midwife examined me and said they it looks like i have got a superficial tear which she can stitch up. However, 2 consultants came and it was a 3rd degree tear. I'm still suffering from this now and its unfortunate it happened. I don't understand why it did happen. I'm was a small framed women why did the midwife not think that there is a possibility i would tear.