Weight loss plateau?

I am doing Brooke’s recommended weight loss plan and it is working for me! So thrilled. I started May 22nd at 153 and did a cleanse and got to 150 by June 1. My goal was to get to 142 (8 # down!) by the end of June. I am now hovering at 146-144-145-146 and can’t seem to lose consistently like I did in the beginning. 145# has been my plateau weight most of my adult life. I got to 136 in 2014-2015. I could not stay there, but did not know this diet plan. Is it common to get to a plateau weight and not be able to break through? I was going down each day the first 2 weeks. Now it is up and down. Love your insights. Thank you.