Im just going to throw out some things that's have helps me with motivation.
Motivation needs to come from inspiration that really speaks to you. Try not to focus so much on your appearance and start focusing on "getting healthy." The best way to get motivated is to start writing or saying positive affirmations to yourself, such as "if I strive for health, my physique will reflect it!" And start motivating others (in person or on forums like this) using these inspiring sayings. You will find that saying them will clouds out any negative things that you have to say about yourself. Find what gets you excited about getting healthy and write down exactly how you feel when you get excited! This way you can read it when you lose motivation to remind you of why you started on the first place.
Also, I signed up for My fitness pal (at
www.myfitnesspal.com) and posted on their introduction thread about wanting some motivating friends. I found A TON of wonderful people that have been motivating me. Try doing this and see if it works for you!
My fitness pal also is great for tracking calories that you eat and calories that you burn from exercising, so when your ready you should look into doing this as well!
Try creating a blog about your journey to a healthier you and having others read it. This will give you a sense of responsibly over your workouts bevause you know that others are holding you accountable! This is also another great way to get in contact with people who will help you stay motivated.
I hope one of my ideas works for you! Motivation van be extremely hard to hold on to, but you can do it! If you need a buddy to motivate you I am a pretty good motivator and will be here for you when you need someone to talk to.