Possible pregnancy

I was supposed to start my period this week. I got cramps and bloated like any other month. But what was different this month was that I was spotting and it wasn't the usual spotting that you get when you know you're about to start your period. It was a different spotting, very light, and an odd color to it. I was also having discharge with it. I'm scared to think it can be an STD or that I could possibly be pregnant. Or maybe my period was thrown off by my coworkers because I work with a lot of females and perhaps that threw it off. Advice would be greatly appreciated. Thank you.