Welcome to the forums!
I used to yo-yo diet as well. I finally came to the realization that I needed a lifestyle change so that I could keep the weight off after I lost it. So far I've done okay except for 5 lbs that krept back on me during the past few weeks (stupid Christmas chocolate).
Counting calories is a great way to loose weight. Combined with exercise you'll see great results! I found it great to keep track of what I was eating during the day (and how much water I was drinking). Made me realize just what I was eating
