Spotting for 6 days

Katie • Mon, Dec 01

I am 6dpo and since then I've been spotting. So I've been spitting for 5/6 days and having back aches. I know I usually spot a few days before period. But if I ovulated I should start my period 12-14 after ovulation, so why the spotting so early before period? I don't get it? Anybody else experience?