Truck is not starting with fresh battery

So I’ve had this truck for about two years and I drive it pretty regularly. Just three days ago I was on my way to work and stopped for a coffee. I get back in and the truck won’t start. The starter clicks over fine and I had replaced the battery and alternator exactly 13 months ago. With the battery under warranty, I got a fresh one in the truck and everything seemed fine. But on my way back home from work tonight, I was driving just fine and noticed the ABS light and battery light came on and off repeatedly (it did this the other day too) but it drove fine until I got home. I tested it out as soon as I stopped and turned the ignition to find the same thing is happening, even with a fresh battery! So now I’m concerned I have a bigger job than I bargained for but I don’t even know where to begin. What should I do?