Weigh loss is not a straight line

But we keep at it because it is worth it.
Also, we all have things that affect our weight... water retention, stress, too much salt, etc etc. It could be anything really. But even if you don't lose this week, you can next week. For a long time I went through a stage where I would lose like 5 lbs one week and absolutely nothing the next... and then another 5 lbs, and nothing. It was an odd cycle but it was what my body was doing at the time *laughs*
You can keep at this. Your body and you are worth it.