10V DC Power Supply help
No, you don't have a shunt regulator.  Q1 is the main pass element.  It is working like a linear regulator.

Q2 is the wrong way around.   You have C and E flipped.  It will still probably have some gain like that, but performance will be better if you flip it the right way around.  The concept is that when the output of the R3-R5 voltage divider gets high enough to be the zener voltage plus the B-E drop of Q2, Q2 will turn on, which will steal current from the base of Q1, thereby turning it off more.

I have no idea what you think R2 is doing.  It makes no sense.