Oscar Pistorius: 'I Have Terrible Nightmares About What Happened That Night'

Olympic track star Oscar Pistorius appeared emotional and tormented as he testified in South African court Monday about what happened the night he shot and killed girlfriend Reeva Steenkamp.

He apologized to Steenkamp's family and told them he was only trying to protect her when he fired four shots into a locked toilet room in the early hours of Feb. 14, 2013. He claims he thought an intruder was inside.

Pistorius said in court that he started taking anti-depressants and sleeping pills after Steenkamp's death.

"I have terrible nightmares about things that happened that night where I wake up and I can smell the blood and I wake up to being terrified," he said. "I wake up in a complete state of terror to a point that I'd rather not sleep than fall asleep and wake up like that."

He also talked about how growing up in violent South Africa instilled a fear of crime in him.

"Everybody in South Africa has been exposed to crime at some point," he said. "When I grew up, we were exposed to crime with house break-ins, family members being carjacked. ... Living with my mother, we were broken into on several occasions."

Pistorius said his mother slept with a firearm under her pillow because she got scared at night.

He also noted that many people know where he lives and he's been followed home late at night.

This explanation of Pistorius' exposure to violent crime could help explain why he thought an intruder was inside his house the night he shot Steenkamp.

He says he woke up that night and heard a noise in the bathroom, remembered there were no bars on the bathroom windows, and thought contractors working on the property had left ladders outside. He claims he assumed Steenkamp was still in bed next to him.

But prosecutors have compelling evidence that refutes Pistorius' story, including testimony from neighbors who said they heard arguing and a woman screaming at Pistorius' house the night Steenkamp died.

Pistorius faces 25 years in prison if found guilty of premeditated murder. He has pleaded not guilty to the charges against him.