I don't know what to think

So my last period started Nov. 2nd and AF has yet to arrive this month. Yesterday morning though I had this brown spotting and it was only the one time I went that it was there. I haven't taken a pregnancy test yet but I will the 19th. I know it could be possible I skipped this month but I'm really hoping I'm pregnant!! I don't know what to think about the spotting and when we went to walk my left side hurt, like it does if you run sometimes. 😕 That kind of scares me!