SAN DIEGO (CBS 8) - An army veteran graduated from Miramar College Friday, and he did it with his best friend by his side. 

Randy Dexter credits his dog Captain with saving his life. 

Just a couple of years ago Randy Dexter's PTSD was so bad, he had suicidal thoughts and didn't want to leave his house. 

On Friday, not only did he graduate form college but gave the commencement speech. 

"Captain is a warrior. He have me the strength to overcome pain," he said. Captain is a lifesaver who coaxed Dexter out of depression. 

Two years after joining the army in 2003, Dexter was on the streets of Baghdad. "On April 5, 2015, I was serving in Iraq as a combat medic when our unit got hit with an IED," he said. 

The blast critically injured a driver in his unit and despite Dexter's best efforts to save his life, his fellow soldier died. 

The guilt was so bad, Dexter was medically retired and was taking 14 different medications a day. 

"I didn't know what PTSD was or that I was suffering from it. I was a prisoner in my own home unable to sleep without a nightmare. PTSD makes the sufferer constantly live in the past or worry about the worst possible future," he said. 

The medicine Dexter really needed was not a pill, but the unconditional love from a service dog - Captain. 

"Because of you - I'm no longer a prisoner in my own home. Just like my battle buddies were my eyes and ears in Iraq, you are my eyes and ears in the states," Dexter said to Captain. 

Now, Dexter is sharing his story in an online video for the organization that united him with Captain, K-9's For Warriors. 

Dexter hopes his story will inspire others suffering from PTSD to realize things can get better. 

Friday's graduation is only the first step towards becoming either a lawyer or a teacher, but Dexter is not sure. What he is sure of is that Captain will be right by his side. 

Visit the K-9's For Warriors website to learn more about the organization.