Don't get too frustrated. It could just be that you ate something higher in sodium and are retaining water. The run not going as planned could have something to do with your discouragement from the weigh in. I know when something is getting me down I have a harder time relaxing while running. Just keep at it. Go at YOUR pace, if you need to repeat a week, or move backwards, don't sweat it, just do it. This is your life, your pace, no need to push yourself to the point you just get frustrated and give up.