How could I tell if I have ptsd from my deployment to iraq in 2010?

Screening exam. You've likely had a couple post deplent exams already if you are out the va can help--startle reactions psychic numbing nightmares increased irritability avoidance of things that bring up memories etc depression may accompany the ptsd--don't self medicate or withdraw from your loved ones at home--seek professional help. Thank you for your service and welcome home!
Sxs + eval. There has been enough time since your return from deployment to ensure that hypervigiliance, avoidance & reliving have largely dissipated. If these behaviors are on-going & problematic- it would be worth evaluation through your local "vet center" or via a department of veteran's affairs medical center.
Talk to a doctor . If you think you might have symptoms after your deployment, seek help. Talk to your doctor, or go to the va! if you were in combat, have sleep disturbance, are jumpy, and have nightmares or intrusive images of your experiences, are irritable or withdrawn from others, you may be suffering from ptsd, or a similar disorder. It is treatable. Get help!