I tried to crawl using the water bucket and I drowned whith full health and my stuff didn't drop for no reason and after that i could stick my head through blocks

My air bubbles ran out and instead of taking half a heart I died immediately even though I had full health. My stuff didn't drop. It should have though. There was no reason for it not to. Then I could stick my head through blocks. The reason I was in water is cause I was trying to crawl but my head didn't go through a block and if it did why did my stuff not drop?