So I am 16 new to minecraft modding, I have done some smaller stuff I.E creating blocks, items, tools, etc. I want to create a system that effects the character in game and all has been going well i have an ingame GUI displaying the level of stamina/energy but the two problems i face of now are overriding the texture gui.icons for my gui bar and also creating a system where the stamina/energy drops over time as a base and drops furthermore by completing actions such as travelling a certain distance or mining etc. any help is highly appreciated!
My attempt at the second: http://prntscr.com/3nmbds
the current texture rendered : http://prntscr.com/3nmbk8