abnormal bleeding week before period

I have been on birth control for a little over a year now. before taking birth control my period was always regular now it fluctuates from time to time. on saturday i was out and noticed what i thought to be blood in my underwear a week before i was supposed to get my period. after telling my boyfriend he began to think that it could be implantation bleeding because it was a pink color rather than red. however now it has turned a normal red but it is not consist. it comes and goes and has for two days now. i called my doctor and she said that it could be due to hormones but i’m still uneasy about the whole thing. just wondering if anyone has experienced this or something similar ? any feedback is appreciated!!