Not in Ketosis

Hi all! I'm back on Keto after being "off" for about 6 months. I haven't lost any weight (3 weeks) and finally bought some Ketone test strips yesterday. I'm not in Ketosis and can't figure out why. Am wondering if I should not be adjusting my carb/fat/protien throughout the day as my goal % change as I exercise, etc. I also started walking 5 miles a day which I haven't done in about a year. I get that muscle weighs more than fat and am probably building muscle, however that should effect my Ketone level. Also, is there a time of day that's best to test? Thanks for your input!