Should I do a test or not?

I have a question. I stopped the mini-pill a year ago and switched back to the regular pill. Due to busyness and stress, I forgot to take it a few times. Now I'm almost 2 weeks late. I did a pregnancy test on Monday afternoon and it was negative. This morning I thought I was starting my period (bleeding), but it was very light and quite dark.. Could this be implantation bleeding? Or is it just my period after all? I'm unsure and wonder if I should take another test or not..