Steve's hearts wont regenerate after hunger bar is full

1. When I started the game, everything was going well until when I lost hearts, my health would not regenerate while my hunger bar was full.

a) I tried switching difficulties (even peaceful mode) to see if my health would regenerate but b) still it wouldnt regenerate even on peaceful mode.

c) I also attempted to restart the game but still, heart regeneration is null.

2. I then attempted to lose hunger by running. Soon after I lost a pip of it, I ate food, BUT still, my hearts would not regenerate.

3. Funny enough, as I was intensely mining, even my hunger bar would no longer lose hunger (on every diffiulty)