You'll find plenty of them whilst out and exploring. If you've infused a weapon and dropped it, you'll get it back the next morning. I tend to drop my least favourite weapon that I am carrying as I can take an alternative for the rest of the day and any weapons I find that I like at night, I just drop whatever I have and take those with me. Not aimed at you but there seems to be a lot of people who went into this game not really knowing how the mechanics worked and then complain when the game does exactly what it set out to do. You're reliving the same day over and over again the only thing you retain is knowledge unless you infuse items. Personally I'd say target the Slabs first (Shift and Nexus were the essentials IMO) as they really change how you can play the game.