Lighter period? Brown blood? Your opinion...?

Ok so here's my thing...I've had sore (which i ussually have before my period). So there i am waiting & I got what I thought was my period coming early, but all I got was dark brown blood. It is very light flow but only dark blood kind of gummy (sorry!) of a different consistency than normal. No red. I do not have any children, I am in a commited relationship so ofcourse i am ually active. Any opinions welcome, thanks for taking your time to answer :-)