You need to get some research points quickly so that you can purchase level 2 of harvesting. That way your villagers will learn to farm and will have a more reliable source of food. To do that, put some of your villagers at the "research table" where they can work on new technologies. I really recommend that you turn on the tutorial the first time you play Village Sim. It explains the basics of the game and warns you that you will run out of berries.