Does Anyone know how to get over nostalgia?

For context I’m a 20 year old male. I often get memories of my past and feel the strongest sense of nostalgia with a pit in my stomach. Why is this the only emotion I can actually feel.

I’ve had a great life, no doubt about it. Does that mean my nostalgia is only worse? I literally have romanticized every previous stage in my life and it hurts so bad knowing that I’m getting older and I’ll never go back.

I had an awesome time in high school and then I joined the military after. When i originally left for the military I was so sad and looked back on my memories thinking they would never be recreated, but they were. I literally yearn for things that happened like 2 months ago. Why is this?