What happens to my bread if i killed the yeast?

so im a beginner. literally this is the first time i have tried to bake bread (in the oven, traditionally?) by myself, and so im like 99.99% sure i killed my yeast. i followed the instructions & let it sit for way more than 30-45 minutes, maybe even an hour, & it hasnt doubled in size like it says it would. so what happens to my bread if i cook it. will i just not rise? :'( i dont want flat bread...