Implantation?

Helen • I am 30 yrs old. Been with my partner 5yrs. He is a guitar teacher and I am a home carer. Bought our first house last year. Now have our first child. A son named Harvey born 27/10/3016
I am 5dpo and today I have had a pinching feeling that lasted about 15mins maybe longer. Period isn't due until the 29th so too early for a test but could this be implantation or could AF be coming early? I do get cramps a few days before AF but this feels different. Does anyone else remember a pinching cramp before their missed period/Bfp?