Some chunks don't load and every block I placed

I was in my friend's creative world and when it loaded I joined and it was full of missing chunks and everything I built just wasn't there for some reason except for all of the entities like mobs and others. Also both me and my friend lost everything in our inventory. I'm playing Minecraft bedrock (pocket) with actions and stuff texture pack so this is why it doesn't look vanilla. This is a big that happened to me before. Please fix it.