heater problems

ok, to make this short. when i wake up early mornings i let my car warm up for about 10 to 15 mins, i turn the heater on at about medium and the last couple of days when i turn it on it like totally squeeks and no heat comes out, and my car runs crappy, so somethin is wrong but i dunno. so does anybody know if this is an easy fix? and if it is do u know how much?

does it blow cold air? or no air? The blower motor squeeking is usually a sign that its on its last leg..
But im not sure why this would have an effect on the way the engine runs.. Does it idle rough? lack power? does this happen exactly when you turn the heater on? Is it overheating? running cool? checked your coolant levels?

The more info you can give, the better idea we can get as to what your problem is

If you have no heat check your hot water valve also if your car has a/c there is a vacum line on the top of the valve jsut replaced mine cost about 20 bucks and 5 minutes of your time