Hi Tinamarie,
Starting you diet and hiring a personal trainer are great ideas to help you achieve your goals. The problem you said you had is one of the most common one's I hear. The truth of the matter is that it is not always going to be easy, but you can do it! If stick to your plan you will see results. Results often help with motivation.
Your example of not liking soda after staying away from it for a while is something I also her from a lot of people I work with. As your lifestyle and menu changes, that can happen with many foods and drinks.
Attack your program everyday (which needs to consists of your diet, cardio and working with your trainer). I bet you're a lot tougher then you think. Take back your life and bring it to a new level of health and fitness.
Good Luck,
Paul Lauer (Fitness Moderator)