First of all apologies for the delay in responding, this site is new and was going through some maintenance over the past few days.
Women often find it hard to detach from relationships. It sounds like you haven’t had closure with regards to this relationship. Deep down you may have regrets regarding unmet expectations, and you may be feeling rejected or abandoned. Maybe this is leading to feelings of low self-worth. You think about it everyday, which means you are ruminating: compulsively thinking about the same problem, helping it to grow inside your head.
You can try writing a “goodbye letter” to him, which you won’t actually give to him, it will help you process your feelings. In the letter write down your thoughts and feelings and cover the range of emotions you are experiencing: anger, hurt, shame, resentment. Try to end it with forgiveness, both for him and yourself. Tell yourself this is closure. After reading over your letter, tear it up and flush it down the toilet, or burn it in the kitchen sink, visualizing letting go of your attachment to him. Whenever thoughts about him enter your mind, immediately replace them with a positive message to yourself like: “I can move on and be happy now”, and force yourself to re-focus onto the present moment.
Over the next few weeks practice healthy habits which include exercise, balanced eating and sleeping, positive social interactions, hobbies, and daily journaling each night where you write down “what’s good about my life now”. A positive self-image, healthy life-style and engaging in activities that bring you satisfaction will help you re-direct yourself. Also please consider seeing a Cognitive Behavior Therapist (CBT) to help you develop adaptive thoughts and behaviors. CBT is empirically proven to be very effective in treating depression.