What Causes Abnormal Bloating And Heaviness In Abdomen In Between Menstruation Cycle?

Hello, today is supposed to be the start of my period and I had a fairly steady flow of watery dark brown/red blood instead of my normal heavy flow of bright red thick bloo . However, the flow has stopped completely for the last 6 hours. I had abnormal bloating and a feeling of heaviness in my uterus two weeks ago and thus have been worrying about possible pregnancy since. Should I be worried?