An unexpressed feeling has no value. Always express how you feel and what you are upto towards your loved ones. A good relationship should involve sharing all the emotions instead of bound shielding it inside the heart. It makes relationship more stronger and happier. Here is a great collection of images listed under the tag name "Feelings". You can share these images to your loved ones to express your feelings.
The sad feeling can never go away unless the person who gave the sadness come back into our life. Even if he/she left sadness, we can't lose any valuable relationships. So make efforts to get back your love. Sharing a heart touching love sad greetings will let your loved one know the hurts and troubles you're undergoing in your life in their absence.