spotting a week before period, am I pregnant?

I’ve been on birth control for a little over 3 years now, the same one, and I’ve never once had spotting or bleeding between periods unless i’ve missed a pill (only happened 2 times and not recently). I’m on early week 3 of my 28 day pack and I’ve been lightly bleeding for the past 2 days along with cramps and some headaches. I’m not supposed to start my period for like 7-8 more days. The bleeding isn’t enough for a pad or panty liner but it’s there when I wipe and it’s pretty light pink. I spoke to my doctor about it and she told me to take a pregnancy test (Im sexually actively) which I did and it came back negative. I’m worried that this is implantation bleeding but it’s too early to show a positive test because I read that it would normally start around 9 days after ovulation, which would’ve been yesterday. Does anyone know what this means? please help me