Implantation??

Katie
So I'm a little sceptical. 
I've had a head ache for 4 days, cramping for 4 days, sore nipples and boobs, I have light pink/red spotting 
And strange cravings (mcds chips and milkshake) ?? Lol 
I never have a headache or this long cramping when AF will arrive .. But I started getting this 8 days before my period is due and I'm now due on Saturday! ?? 
Could I be experiencing implantation? Because I'm 50/50 
Tested but I know it's too early (negative )
Any experiences ?