It is normal in some situations like you have experienced, loss of a job, loneliness, guilt, to be depressed. However, wanting to hurt yourself and end your life contradict the most basic natural instinct, self preservation. You said you have not eaten in three days. Many neural transmitters are in the gut. Food sensitivities, malnutrition and diarrhea or constipation can also lead to depression. Please eat some healthy food loaded in vitamins, minerals, omega 3's, some protein and antioxidants. Your body requires nourishment for body and especially mind health. You will be surprised just how well a properly balanced diet can help all aspects of your life. I already prayed for you. Be blessed.