Feedback: I’m not surprised you’re so upset. Anyone in your situation would be. And it sounds like you dealt with it with consideration and dignity, by hiding your sadness and disappointment and enjoying the wedding. You held your head high.
Ideas to move on: Talk to him. When he’s come back from honeymoon and settled back into a routine, ask him out, just the two of you, to a public place (for a walk or lunch or something), so it’s less likely to get heated, but where you can talk openly without being overheard. Don’t dive straight in. Say you loved the wedding and you’re so proud of him, love his wife and her family and your grandson. But you were very hurt he didn’t want to mention you in his speech and you wondered why this was.
Be calm and don’t paint yourself as a victim. Don’t be attacking or accusatory. Just ask why and be ready to listen to his answer. You don’t have to respond if his answer upsets you, like ‘I didn’t see the need, you know I appreciate you’. It’s clear you realise he hasn’t had the best male role models in his life, to teach him to appreciate you. But simply let him know it hurt and let that sit with him. How he deals with it is then up to him.
However he reacts, try not to let it ruin your relationship. As he gets older, and realises how tough it is raising kids, he’ll no doubt appreciate you more. But, especially if he’s your only child, better to try to develop an open, honest and close relationship as adults, and to be in your grandson’s life.
But set some boundaries going forward, as he sounds quite inconsiderate and unappreciative. He shouldn’t have asked you to look after your grandson at the last minute ahead of the wedding without making it clear what a big ask that was and how much he appreciated it. You’re not his servant. He’s a man now.