I'm honestly in shock right now because this came out of absolutely nowhere. I have a 2016 Mazda 6 that I drive every single day for work and errands, and it has never given me any trouble at all. Yesterday I drove to the mall, then to the grocery store, then home, everything was completely normal. The car started fine every time, no strange noises, no warning lights, nothing. This morning I came out to go to work, put the key in the ignition, turned it, and absolutely nothing happened. No clicking, no cranking, no dashboard lights, no radio, no headlights, nothing at all. It's like the car is completely dead. I checked the battery terminals and they seem tight and clean. I even tried the headlights and they don't turn on at all. I don't understand how a car can be perfectly fine one day and completely dead the next morning. My neighbor said maybe I left a light on overnight but I checked and everything was off. I don't have jumper cables and none of my neighbors were home to help. I've been sitting here for an hour trying to figure out what to do. I found a how to handle a car that refuses to start online that mentioned checking the battery voltage, but I don't have a multimeter. Could a battery just die overnight for no reason like this even if it was working fine yesterday? Or could this be something more serious like a blown main fuse or a bad alternator that drained the battery somehow? I don't even know where the main fuse is located on my car to check it. Is there anything else I can try on my own before I call a tow truck and spend money I really don't have right now? I'm so stressed because I can't miss work today and I don't know anyone who can give me a ride. Any advice for a complete beginner would be so appreciated because I feel totally helpless and I don't even know what questions to ask a mechanic if I do get it towed somewhere.