5day periods for 3 years then all the sudden I have a 7day period?What's the deal?!

Okay kinda freaking out- since I had a baby my periods have been 4-5days long. We decided to ttc more accurately this cycle and I have a 7day period for the first time in 3 or so years. The last few days have been light flow and spotting to brown with this awful funky smell that I cannot put my finger on. I use cloth pads and a menstrual cup as well and this odor is not a common thing. Why is it SO long? Should I be worried?