In the novel “The Great Gatsby,” Nick Carraway said to Jay Gatsby, “You can’t relive the past.”

He replied, “Of course you can.”

Gatsby was right. I went to my high school reunion last week and suddenly I was 17 again.

The class of ’69 came in with gray hair, white hair and no hair. A 50-year high school reunion looks like a live Q-tip convention.

The moment I entered the room, my first thought was, “Who are these people?”

Reunions have a certain and immediate awkwardness to them. You walk around and your eyes are looking at total strangers until you stare down at the yearbook’s young faces on their name tags and then you announce their names as if you are a teacher taking attendance.

“Robert Schaefer!” I heard someone say behind me. “How are you?”

You hear the same words spoken. “I remember you.” And then it’s all aboard, traveling back in the time machine.

We made a stop in Mr. Fox’s class. We’re taking one of his fill-in-the-blank tests and I’m looking around the room. I see Dave straining his neck to peek over Kathy’s shoulder to see her paper. I see Sherry flashing hand gestures alongside her chair spelling sign language answers to Peggy, who sits across the room near the windows.

“Signing” was a primitive form of texting back in our school, and it seemed like all the girls knew how to do it. Sometimes an outburst of laughter meant they were making fun of one of us boys. I always thought it was me. Mike thought it was him. Bob thought it was him. You get the picture.

Speaking of Mr. Fox, he walked over to our reunion table and we were shocked to discover that our teacher has been carrying only a few more Social Security years with him than we are.

We swung our chairs around and jumped back to the terrible night of our junior prom. That afternoon a history teacher from our school murdered our Spanish teacher at a traffic light in the middle of a busy street. She was supposed to have been a chaperon at the dance.

“How many years in prison did he get?” I asked Mr. Fox.

“Seven,” he replied. “He was released on appeal because he was found innocent by reason of insanity.”

We laughed, but not a funny laugh because we know that the “insane” guy is married now and living somewhere in South Jersey.

Debbie stepped up near me at the reunion bar. Since we hardly knew each other in school, I forced a conversation about gym class and the uniforms we had to wear. She reminded me that the boys wore black and gold, our school colors, and the girls wore all red for who knows why.

Back then, boys and girls had separate gym classes. The boys often played “Bombardment,” an extreme form of dodge ball. At our table we recalled the day when our gym teacher threw out five of those hard red dimpled rubber balls for us to attack this one kid that we knew to be a bully. After we bounced the balls off his head several times, he screamed and ran out of the gym.

“Get him!” The teacher shouted.

We chased him down the hall, and somewhere near the foreign language labs, we hammered him with the balls so hard his arms had red dimple marks on them for the rest of the day.

Do that today and the kid’s mommy runs back to the school with the Edwards, Wilson and Jones law firm by her side. Back then we took care of business our way. That kid never bothered anyone again.

The night moved along. We had a moment of silence for our classmates who passed away. Car crashes, cancers, suicides, drugs and Vietnam took the lives of cheerleaders, straight-A students, football players and the kids next door.

Fifty-year reunions mark mortality. Once we were teenagers who thought that life would never end; now we breathe through the last cycle of our time on earth. We are grateful for each day. Looking around the room, you could see that some of us have aged gracefully and some have not. That does not matter. We are all still alive.

We spent one evening together, frozen in a time warp when assassinations changed the world, a man stepped on the moon, and a half a million hippies held a three-day rock concert at Woodstock. What happened outside our school was insignificant to those of us who were busy coming of age inside the walls of Piscataway High.

You could feel a heavy sadness through the hugs and the goodbyes at the eleventh hour. Someone kiddingly said let’s have our 75th reunion at the Happy Meadows Nursing Home. I kiddingly replied, “How about we do our 100th in the Rolling Hills Cemetery.”

The truth is that this reunion was the last time many of us would see each other. I felt like I wanted to grab the moment and hold it back so I could to take in the faces of all my classmates as they exited through the door into the dark night of who knows how many more tomorrows.

The past is the past. You have to move on. This is true, but we carry memories with us and we keep our gone by days spent in high school stored someplace in a box to open again when something reminds us of the way we were.

Rich Strack can be reached at katehep11@gmail.com.