am I menstruating or should I see the doctor?

I thought I started menstrauting yesterday because there was light bleeding. But it did not get heavier. I didn't even wear a pad during the day. I wore one last night and it came out clean. 
Today the bleeding is not even red, it is brownish. I don't have to wear a pad at all. Is it possible to menstruate for a day?
This app said that I was supposed to start today too. 
Am wondering if this should be told to the dr. I have never had light bleeding like this before. 
Ttc for 1+ year and had bd 3 days ago.