On Clomid my LP is usually about 15-16 days. I'm not really sure without it, as I wasn't tracking ovulation, but my cycles were close to 35-36 days in total. I think 18 isn't THAT long, not really that far from the average of 14. Yep, 12-17 is normal, but I still think18 doesn't sound too long. You have just got the implanon removed, so maybe that is causing some changes as your cycle gets back to normal. I would just watch it over the next few cycles, and maybe see a FS if you find they are still 18 days or longer...