Last week, as she walked out of class, half of her body went numb, she had a hard time seeing and couldn't put words or thoughts together.
"I realized I couldn't see my right hand, and I realized I was getting confused and I knew something was wrong," Castro said.
She began to panic. Struggling to speak, she texted her friend Rebecca Corona two simple words: "help, help."
"I ran up there and she just kept repeating that she couldn't think and that she couldn't speak," Corona said.
Corona and their friend Dawn Murphy dropped everything and found Castro near where they always study.
Castro pointed at Murphy and said "call 911."
"That I needed help, that my friend couldn't keep a thought, I didn't want to say stroke and so I just talked through her symptoms and stuff," Murphy said.
Paramedics rushed Castro to the emergency room, where doctors said she suffered a mini-stroke due to a small hole in her heart that clotted.
Doctors told her if her friends hadn't acted so quickly, she could have suffered severe brain damage.
"They saved me, they saved me, they saved my life, and everything I can do because of them," Castro said.
"We just built this amazing friendship that I could never see my life without either one of them."
All three will graduate and transfer to UC Irvine together, their bond stronger than ever.
"You want to know that your friends will be there for you and I have proof just standing here that they'll be there for me," Castro said.
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