Eat Stop Eat, Leangains, and Venus Index

Hello all. I am a 35 year old single mom of 3 and 5 year old sons, teacher, business owner, and former fitness and Group X trainer. Fitness is a HUGE part of my life and I even taught Spinning classes up until the day I gave birth to both kids. I gained about 25 pounds with each pregnancy and easily went back to my pre-pregnancy weight within 6-8 weeks through proper nutrition, breastfeeding, and exercise. I am feeling SUPER frustrated after gaining 12 pounds in four months from the Mirena IUD and had it removed 3 weeks ago. As always, I eat very well and exercise 6 days a week doing both cardio and weight training. I religiously log my 4 weight workouts and 45 min of cardio 6-7 days a week plus the 1200 daily calories I am allotted and rarely go over my goal. The weight is going NOWHERE!!! I purchased the Venus Index last night because it reminds me of how a trainer used to work with me, very light cardio since I lose my lean mass easily, and more of a focus on resistance work. I was really interested in the Eat Stop Eat and Leangains theories because I naturally always ate this way but thought I "HAD TO" be eating 6 small meals a day to get back in shape and drop the weight. With the mini meals I am starving constantly and can't stand it. I'm getting so depressed because I am doing everything "right' according to the textbook, and for the first time in my life and really struggling with my weight. Please give me any feedback on these programs and thanks so much.