Is This Normal?

My period started two days ago with out me knowing. I've been spotting for the first two days of my period I just want to know if this has happened to anyone else. I'm 16 I've had my period since I was 12. My period is always heavy the first 3 days and it's kind of freaking me out that I'm spotting because I've never spotted before. I'm planning on visiting my doctor soon. I just want to know if this has happened to anyone else😞