79 GMC Sierra Truck Died Unexpectedly

I have a 79 GMC Sierra that I use for snow plowing. I drove the truck a few miles once a week or so over the summer and it always started and ran great. I had just hooked the plow back up (the electrical was never removed, just the blade), started the truck and was raising and angling the plow blade to make sure I had everything hooked up correctly. After a minute or two of doing this the truck stalled and I couldn't restart it. After several tries to restart the truck the battery seemed to lose juice. I tried to jump start it to no avail. Now, if I let it sit for an hour or two and try again it tries to turn over but doesn't catch and then the battery seems to die; however, the dashboard lights do come on. I know that it has gas in it so that shouldn't be the problem. Any thoughts? Might have flooded on you, by loading up the engine before it was completely warmed up? Check or block the choke plate open in the carb or pull a couple spark plugs and see if theyre gas fouled. Make sure the battery is fully charged, then load test it, may be weak? Worst case too is the starter is also dragging and may be on its way out. los