My 95 Z71 has many problems HELP!

I have a 95 Z71. Its a 350 TBI with a 5 speed trans. It can be very sluggish, it starts fine but is gutless at many time, gutless as in, NO BALLS! Its quite irratating, and I was driving it today on my way to work and it was sluggish again, then, my volts when down to about 12 instead of being up at 14. And my temperature gauge went down to about 130. I shut the radio off and turned me weak wipers at the time off also. I also turned off any accesories and lights. Then about 5 minutes later while driving, my volts go back up the temp goes up to 210, and its not gutless anymore. What the hell is going on.
Also my control unit for my hot/cold settings and where to send the air module is not working, I turn it on and i have no heat nor where i want to blow it. I just have a fan blowing air.

Sounds like your alternator or battery is going bad or has a really bad connection somewhere.

I drove it home last night, got really funny again, popped the hood, steam everywhere along with coolant everywhere. This is bad im sure. Head Gasket?

Could also be a radiator hose, heater hose, or the intake manifold gasket.

actually i had a weird leak on the water pump gaskets, causing coolant to shoot everywere, it got on the distributer causing missfires, also on the belt so it wasnt turning the alternator at regular speeds.