Try upping your water intake if possible. You could have just hit a nasty stall. Keep with your plan, but try to change it up a little bit. I find, if I play with my carbs every few days or so, I tend to kick start things up again, by staying between 20 and 40 for a few days, and then kicking it up to 50 for a day. Make sure you also do this with your protein too, to keep the ketosis going. If I have a handful of bbq soya beans, as a snack which has awesome protein, but just as much carbs, it fuels my body better, but only do this once a week or so. It keeps my body guessing, and not get stuck or comfortable and continue burning.
Sometimes you just have to wait it out. Patience has always been the hardest part. That is why so many of us would give up on traditional diets. Don't forget to measure. I've heard that our bodies can not loose lbs and inches at the same time, and our bodies need time to adjust. If you are a light weight like me, then it's a fact that we tend to lose at a slower rate than others. A 2 to 4lb average loss per week is a good steady loss early out, so you seem to be on track. Don't get hung up on the scale number, rather judge things by how your clothes fit. Just stay focused and if you haven't started vigorous exercise yet, this may be a good time to start incorporating some activity to help kick start the metabolism. Good luck.
HW: 235 SW:227 Preopw:218 GW:120 HT:5'3