My advice would be to throw the strips away. I've heard from too many people that they are inaccurate. The reading can change depending on how much fluid is in your system, what and how much you've eaten recently, and other things. If they are showing even a trace and are eating under 20 a day then you are probably in ketosis. If you haven't lost weight it could just be that you lose really slowly. I only lose 1/2 to 1 lb a week - at best - even in strict induction. Also, the closer you are to your healthy weight, the slower it will come off. It could be that you aren't doing anything wrong, but rather that you just need to be patient. (I know that's hard - I have to remind myself everyday.)