Implantation or signs of early period?

This is the first time I've experienced brownish blood strands in my undies 2 weeks before my period. Keep in mind I have very long cycles and an never regular. I have been have mild twinges and crampa. I also have noticed the past 3 or 4 days I've been really moody. The head aches I've been having aren't really normal they are just there enough to notice and my vision is slightly blurry. I'm wondering if I should be concerned and run to the dr or if it's implantation bleeding. Me and my boyfriend aren't trying to get pregnant but we are using the pullout method. We have been together for 6 years.