Battery draw/ drain while running

So a week ago I I into a gas station in my 99 dodge 1500
5.2 .to get gas when I was leaving the battery died. Got a
jump just fine dice home. The nextday I was drivingto work
and my check gauges light came on and my battery was
drained. I pulled over to see if it would bounce back butit
didn't, it drained all the way and shut it self off... I thought
right away alternator I tested it, battery and starter and
alternator failed iI and anew once installed it, started and
drained... shut off. Battery is only a year old so my next
thought was ignition switch. Changed it and still draining... I
don't know what else to look for... please help