HP Bar Bugged Out

I was playing Rammus Jungle. Everything was fine until I started the first camp. Im not sure if it was before or after I smited but what happened was my HP bar dropped to 0 and remained that way for the rest of the game. The NUMBERS in the hp bar were correct and the game functioned as though I had the correct HP. However, the bar itself was empty and would flash red every time I took damage as though I had like 5% or less hp. So I had to read the numbers carefully throughout the game and try to base my play off of that. So, again, the NUMBERs were correct, but the BAR was empty the whole game as though I had 0 hp.