Hi, I think if you had an infection you would really know about it, does it smell etc? I think it is pretty normal for AF to be a bit strange for a while, sometimes it can alter for good, I used to have a 7 day AF then after first DD went to 3 days and very heavy??? I have clots every cycle, I think it is due to it being very heavy, or like the others suggested maybe you did have an early MC if you are concerned contact your doc.