The consistency of the menstrual blood can vary depending on the day of the menstrual cycle and also on increasing age. Of course, any infection would reveal itself as cramping or dull pain, foul smell in the discharge and associated urinary tract
infections at times. You can have some clarity if the discharge can be tested, both biochemically and for any pathology. Please maintain proper genital hygiene, do not use tampons, and strong soap solutions. General infections also can be another possible cause. Hope this helps.