Sometimes the best fitness instructors are people who have battled weight control problems themselves and can relate very well to people who are going through the same issues that they have already faced.
Experienced fitness instructors have seen it all before. Many people avoid personal training because of embarressment of their present physical condition. It's up to you to make the first approach and contact a personal trainer. They will be able to put your mind at ease and reassure you that your goals are possible no matter how much work there is to do.
Fitness Instructors are usually well networked with other people in the health and wellbeing industry. They will be able to refer on nutritionists, massage therapists and lots of other people who are there to help you with your individual goals.
If you are just starting out getting fit again after an extended period without exercise you should find yourself a private personal trainer who can get you up to a level where you can go to group training without holding back the rest of the group. This person will also be able to build your confidence up to a level where you feel more comfortable with your self image and also able to establish a good routine - by working around your availability.