What Causes A Delayed Menstrual Period After Failed Attempt To Insert Mirena?

My doctor attempted to fit a mirena coil for me at the end of February. She couldn't do it as i was in too much pain. I bled for a couple of days afterwards. I have not had a period now for nearly 8 weeks, considering i am normally fairly regular i am rather worried. I have done 3 pregnancy tests and they are all negative. My nurse says the trauma caused to my womb would not have an effect on my cycle. I am worried something else might be wrong. I have been putting weight on steadily for the last two months despite exercising and cutting down of food intake. Could the lateness og my periods be caused by the attempted coil fitting?