Hi, I also had very strong implantation pain on day 27 of my first cycle. I had very bad lower back pain and severe abdominal cramping. It was the strangest feeling, not like period pain or anything else that I have experienced before. I also asked for some pain killers and was not sure what the pain was from. I thought I might have had a really bad urinary tract infection or ectopic pregnancy. I had to lay down, could not sit or walk around. I eventually took some panadol and fell asleep. The next day it was all gone. I did a pregnancy test and it was positive. I guess that means that it was implantation pain. It really confused me because I did not have it at all with my first pregnancy. Thank you so much for your posts. Its really reassuring to hear that other people have felt the same thing. ox