Implantation

Amanda • I am 23, engaged to be married, our first is a beautiful 5 y/o angel in heaven, We lost her April 2015, miscarried our second October 2014, we are waiting for our rainbow after the storm. (Ttc 2yrs)
So I am pretty sure I had implantation bleeding this morning, just light pink spotting when I wiped then nothing else. im 8dpo and one week before expected af.....well now since then I keep getting period like cramps off and on like im af is coming.....is this normal? Is af symptoms similar to implantation?