How do I solve this dilemma?

I'm in the process of loosing weight and i'm very unstable with my goals. I do moderate-high intensity exercise 5-6 days a week (1-2hrs) and love it! I'm just not motivated to change my way of eating (i overeat), but i don't do any fast food or pop kind of things. I'll go steady on loosing 10-12lbs over a month and then if i'm not in the mood to loose weight i'll usually go back to my old ways and gain it back. It's a repeated cycle(and i do keep exercising during that period). I know how to eat healthy, and have a meal plan created by my nutritionist that i do like, but don't follow consistently. It's not a diet..it's very real...i'm just not sure how to get my mind straight. It works like this: as long as the feeling stays, that's how long my weight loss stays off. I know that i want to fit in smaller clothes and look better. I'm just stuck in a comfort zone and in a "gave-up" mode and can't get out of it. I don't know when i'll make the decision to change my ways...and start over. I'm so sick of gaining lbs right now and yoying so often. PLEASE HELP!!!