I am having depression after returning from overseas deployment. Where can I get help?

Medical corps. If you are active duty then you have access to well-trained physicians who are experienced in recognizing and treating this (i was active duty primary care for 7 years). The medical corps takes it seriously and will do what it can to help. Make an appointment and have this addressed.
Call the VA. If you're a veteran there is help readily available for you. Call the va crisis line and someone there can assist you in getting an evaluation and treatment. That's what we as taxpayers pay them to do for our veterans. Thanks!