A little insight please!

Here is my background: I'm 24 y/o, I'm on the end of my 3rd cycle ttc #1, cycles are 25 days long. Today was supposed to be the first day of af, but it didn't start the way it normally does? I don't want to get too graphic but in early morning there was brown blood, then a few hours later when I went again it was a bright red blood (just a little) now its back to brown blood. Its not enough to where I'd need a liner. I don't feel pregnant nor do I feel like AF is here. Is it possible I could be pregnant?