How can I keep my commitment?

I've been trying to lose some weight, eat healthier, and work out every other day. A few months ago, I was doing this perfectly. I was eating right, I was working out almost every day, and the fat started to melt off my body. I was happy about this but I only did this for about a month then one day I started over eating then eventually stopped working out. I'm almost back to the weight I was before I started working out and everyday I struggle on just getting myself to eat right! What do I do? I really want to be committed to a healthier lifestyle but I seem to not be getting anywhere! Any advice? Thank you in advance!