Sunflower, I am cheering you on! I know you can do this. I TOTALLY understand the not losing thing despite being OP and feeling defeated in a way because when the scale moves it keeps the momentum going. However, I am confident that you will get there soon. I think you have a lot to celebrate already because you have lost close to 20lbs which is amazing! Congrats on that.
I was speaking with my mom this weekend, who is a diet pro, and been on everything imaginable...including IP (she had success but slow) and she said that a cheat day/meal can be a good idea to not only relieve some of the mental exhaustion that comes with dieting but also can be helpful in mixing it up. While you may see a 1lb gain, it may kick start your body to work on those carbs/fats. She and I were talking about why the scale has not moved for me and she suggested giving it a shot to see if anything happens.
Good for you for picking back up OP and setting a new mini goal. I will say that when I did IP the first time around in 2012 my coach was not allowing me restricted...in fact I had no idea what they were until I was snooping around on here and went back and asked her. She said she doesn't like to use them b/c people loose more. Anyways, give it a shot. I think you will have some success!
Remember we all want this for you! Go girl!