Don't worry, that is the usual way you end up dying, lots of things can get in the way of food production. You unlock farms in castle upgrades, subsidise them to get em off the ground, and then people should start working there. From there, there are various strategies to increase production, but that's the basics. It might be you've run into a genuine glitch tho, if you want to send me a screenshot then please do.
Thanks for playing and commenting :)