Could I be pregnant? help!!

Okay so my fiancé and I have been trying for a year now. I started on the 26th of this month and when I first started it was brown then to pink and then really dark red and on the 27th my fiancé and I had unprotected sex and late that night on the 27th my period stopped. Now today I was standing up and I felt just like I wetted my self so when I went to see what it was I had brown discharge all on my underwear I have no cramps and I was cramping a little when I started my period but wasn't near as bad as it usually is. I do have irregular periods I just can't remember this kinda thing ever happening to me. So please help I need some good advise on what this may be. Thank you!!