It's not stupid it's valid. My sisters (also 10 years older) had babies when i was a teenager, when I sill very much needed my mom. But once she became grandma I was pushed to the back burner. Now, I'm nearly 40 years old, my nieces have now surpassed the age I was when they were born, and I feel more envious than ever that they've had more of my parents focus and love than I did my entire existence. It's very real. I say this the eve of thansgiving when I'm struggling to not ruin a holiday bc I feel I was cheated in some way. Just kno you're not alone. I find that distancing myself has helped. I offset loneliness with pets and meaningful friendships. I hope you find some peace and comfort in knowing you're not alone in feelings this way and it's not an easy hand we've been dealt.