2001 Dodge Ram Turning over / electrical

I have a 2001 Dodge Ram service truck. For a while it has taken much turning over to start, usually first round of 5-7sec of turnover and still wouldn't start but I would then stop for a few secs and then repeat and it virtually always started on the second try within a second or two.
So, it has been this way for the last 8 months or so and otherwise running fine. Today I went out to leave, after having last driven about 7-10 days ago, and the truck did the initial 6sec turnover but the second time the power came on as the key hit the sweet spot but there was only a click, like a nearly dead battery makes, and then the power went out. No lights no nothing. I tried turning the key all the way back to AUX and initially got nothing. I turned the key through its range several times with no response other that a faint electrical buzz when I turned the key all the way to turnover. I thought that the battery was dead after the time not driving it and charged it. After several hrs charging I was able to get full dashboard electrical response but when trying to turnover the engine I was still getting the "Click-bzzzzz" sound of a low battery. I tried turning over several times and even tried the START function on the battery charger to no avail and eventually as I turned the key around the electrical response seemed to get somewhat spotty especially around the AUX position. The last thing that convinced me to stop experimenting was when I turned the key to AUX position and I would get all the electrical on the dash lite up and normal looking but the radio looked like it was having seizures, flickering on and off at a very high rate of speed.
Please help me as this is my work truck and my sole source of transportation. I'll be extremely grateful for any assistance that can be provided.