Should I be worried?

I found this in my undies this morning. I’m not sure if it’s a tiny bit of blood or just darker discharge or what. Anyone had anything like this before? It seems to have stopped in the past hour or so. I haven’t had sex recently and I have no pain. I can feel baby moving around normally. Should I call my dr? One time I called her for spotting after sex and she wasn’t worried. I’m 26 weeks.