Mission Hills High School senior Anthony Vaeao, 18, collapsed during the last period of the day at the school about 2:50 p.m. Thursday, according to the San Diego County Sheriff's Department. He was pronounced dead at a hospital a short time later."Our athletic trainer, our health aide and campus supervisor were performing CPR and they had the A.E.D. hooked up. They did their job," said Mission Hills High School Principal David Cochrane.The San Diego County Medical Examiner's was scheduled to perform an autopsy Friday. Vaeao was on the school's varsity football team and his grandmother, who helped raise him, told reporters that he was a happy kid who was never sick."I went to the hospital and he was gone. I didn't have a chance to talk to my grandson, he was gone I miss him so much. He was supposed to graduate next month, what am I going to do without him? I raised him. He was a healthy kid, never sick," said Sepoima Vaeao.Tributes to Vaeao were posted on Facebook, and a candlelight vigil was held at the school Thursday night.Grief counselors were at the high school Friday morning, and a memorial of flowers, cards, and candles were displayed outside the school. Many tearful students signed a large banner that read, "We love #58." "When I just found out, I just thought it was a joke; I couldn't believe it. I was waiting for someone to say he's OK, he's coming back," said student Jasmine Cruz. The 320-pound offensive lineman was known as a "gentle giant" on campus. "He gave you those big bear hugs, always made you feel good, always made you smile," said Cruz. "It's hard. These are good kids, and things that shouldn't happen to good kids puts your life in perspective what's important, said Cochrane. Dozens also attended a candlelight vigil for Vaeao on Friday. Friends say they will miss the star football player but that they have each other to lean on. "Like coming together as a school and like, everyone comforting each other... it's definitely gotten easier," said student Dominic Darby. Family members told 10News Vaeao was healthy, but some friends said he often complained about his long walk home from the school in San Marcos to Escondido. "He would just mention, like in tweets and stuff that when he was done walking home he would just feel like he was dying, he was exhausted," said friend Samantha Stevenson. In one tweet 10News found, Vaeao wrote, "Why is it every time I walk home I almost die? Thank God I'm still here." That tweet was posted Wednesday, the day before he died. Vaeao, an only child, planned to attend college in the fall, having signed earlier this year to play football in Arizona Western College.