I don't understand what went on this cycle.

First of all, my cycles are always 27-29 days long and Glow is now telling me that this cycle is maybe going to be 35? It's currently CD 30 and I feel some mild cramping with a smallest amount of pink when I wipe so I expect AF to show either today or tomorrow. I'm just having a hard time understanding why additional days were added to this cycle. Does anyone see anything on here indicating how or why that could have happened?