It is a lot easier to stick to an exercise program if you have goals. For example, "I want to lose 15 pounds before July", or "I wanna look like Brad Pitt in 6 months", "or "I want to be able to run 10 miles without stopping". My personal goal right now is to be able to throw a fastball 90 mph. I've has this goal for about a week and i've noticed that since I made this goal for myself I have been working out regularly, working out harder than usual, feeling more energetic and eating super healthy. Before i had a goal I wasn't going to the gym at all because I didn't have a good reason to.
Like I keep saying, exercise is one of the best cures for depression symptoms like insomnia, low self esteem, and low energy. So do yourself a favor; set a goal for yourself and get started. Some good goals to start with could be: "Get to the gym 4 days a week", "do aerobics for 30 minutes a day before work" or "lose 15 pounds before the summer". If you already work out regularly then you should challenge yourself even more.
Hope your feeling well