the stone on my promise ring fell off and i feel terrible and devastated

My boyfriend got me a pricey ring on a college student’s budget. He worked really hard to afford it and now the expensive stone is gone. i feel like absolute shit. i know there’s nothing i could have done but it hurts and it hurts even more seeing him devastated over it. weeks and months of hard work, gone. i wish i could turn back time i wish i was more aware. i’m looking for a ring to buy him right now but i don’t know what to do to make it all better. i really love him and i need to show him he means so much to me when this incident makes him feel so unloved.