I was recently diagnosed with depression and I totally understand those feelings of dispair. Sometimes the only thing that keeps me going is knowing that there is at least the POSSIBILITY that tomorrow will be better than today. That's a possibility we would never get if we acted on our suicidal thoughts.
Suggest to go to the E.R. and tell them how you are feeling. Anti depressants can help but it takes weeks for them to take affect, so don't wait to get help.
It is possible that it could go away, but unlikely. Have you considered being on anti-depressant medications? If you have health insurance then you might be able to see a medical counselor. Your doctor can also provide you with medication and/or counseling.