Chunk and Lag Issues

Hi there,
I have recently played Minecraft and I am having these issues based on playing.
The first one is the loading of chunks. Although I am playing at reasonable speed and wait for the the chunks to load, however, it does not.
Secondly, when I am mid-air in creative mode and wanted to get down, I tapped the spacebar twice. But also, does not respond, yet goes up more or stays. And with particles taking action, I have huge lag spikes every second and doesn't top till I play it the next day, even without them.