I know this is like STUPID simple stuff, but something is just not adding up, particularly I3..... Please tell me I am not going crazy.

 

First we find Rt resistance

Rt = R1 + R2||R3 = 150Ω + 100Ω/3 = 183.333Ω

So

It = I1 = Vt/Rt = 120V/183.33Ω = 0.65454545454A = 654.54545454mA

Next you need to read this example
http://forum.allaboutcircuits.com/sh...04&postcount=8

 

Where are the numbers at the bottom of your post coming from? Most of them are clearly wrong, assuming they are refering to the quantities that seem most reasonable.

 

I think that you managed to swap the 100Ω and 150Ω resistors in part of the calculations in the first three rows.