Weird period

Back in June my period lasted three days which is uncommon since be always been 5 days since I finally got my period back after my son was 18 months. He's now 26 months so last week my period came early on the 19th instead of the 21st but it was barely filling tampons this lasted about two and a half days and nothing two days later I had brown discharge that was barely there now today I just experienced spotting as I went to the bathroom this morning. We did have sex last night but it wasn't rough or anything. I have no idea what's going on  I'm going to schedule a doctors appointment but we have been trying to have a baby but I have no idea what this could mean if i should be concerned any ideas?