Could I be pregnant?

I started a new pill last month. I started what I think was my period a week earlier than i was suppose to. This month I started lightly spotting a couple days before the spot where I started my period last month. It only lasted 3 days. It started off light pink then the last day was brown. I’m worried it may be implantation bleeding. I have been having umprotected sex but I have not missed any pills. I took a pregnancy test a day after I stopped bleeding. It wasnt a early pregancy test and it came up negative. So I think I may have taken it too early. Should I take another one? Or not worry?