Early period!!!!??!? Really need advice!

My period came 10 days early. It's never early. I started bleeding after I had some intimate time with my boyfriend. not penetrative sex. Just some finger action. But I started bleeding with red blood. We read up on it and apparently I either am stressed, pregnant, or have cancer. What worries me is that today, all that's been down there is brown. Not discharge per say but spotting. And I don't think I'm pregnant because me and my boyfriend ALWAYS use protection. It broke and he immediately pulled out right after it happened. He didn't cum inside me or anything. But I just don't know if I should be worried? I feel like it's stress causing me to start early but I'm scared it'll be something else????