Crashing whenever I mine about five blocks without placing more...

  This is strange, when I mine about five blocks, my game freezes. I can't take screen shots because my game freezes. It's SUPER anoying. This means I can't mine or cut down trees without my game crashing within 10 seconds. I have found out a way to get out Minecraft easier, though. I just have to click the windows button, go down to the Minecraft tab, and close it. Then I have to open it back up, again, And join my sister realm. AGAIN. I'm not trying to be mean, because Minecraft is a REALLY fun game, But this bug makes it super hard to play.

   About every five times I have to leave and rejoin, I freeze, kind of. Like, I can still move. But I can't mine things or walk around. I'm stuck in one area. Then I have to leave and rejoin again. It goes back to waht I talked about in the first paragraph after that.

   This is really annoying, and from what I can see, no one has the same problem. This bug has been going on FOREVER! And I really hate it, I finally found this little place to tell you dudes. Please help me. I really wanna hang out in the realm my sister made without being scared to mine or cut down a tree. My sister had to build my home for me.  Please help me with this.