It doesn't sound like your period, I would say by what you have described, it's more spotting.
As you've only been on the pill for 15 days and still on the first pack, wait.
It's going to take a while for your body to adjust to all the artifical hormones you're putting into it. It can take up to 3 months for your body to adjust to it. If you're still having a problem, see your doctor.