Implantation Pain

Sunni • 27 years old and married to an amazing man. Have been trying to conceive for a year. Had an ectopic pregnancy in March this year. Hopeful for the year 2016
Has anyobe ever experienced implantation cramps for three days? I had a little spotting this morning when I wiped myself after peeing, it was a brownish colour. I'm 8dpo and have been experiencing period cramps for the past three days