99 Mountaineer rattling sound

I have a 99 mountaineer with 70,000 miles on it. Recently my car stalled out on the highway and upon opening the hood I saw there was no antifreeze and there was a little smoke coming from under the hood. I had it towed to a mechanic the next day as it continued to stall after adding antifreeze, and light smoke was coming from the oil shaft when I checked it as if it were burning. Mechanic stated I had faulty fuel pump and replaced it, along with full tune-up replacing plugs, changing fluids, etc. I got the truck back today and although it is running ok, acceleration is a bit slower than it was before, like I have to press the gas harder to get speed than I did before. Smoke still emits from the oil shaft, and I dont think that is normal, is it? An addition to that, there is a slight rattling/clanking noise when I first hit the acceleration, and then abates a little as I pick up speed. Also, when I am stopped at a light, the car shakes a little more than it used to, and gets that feeling like its about to stall although it hasn't yet. The mechanic said I might have a blown head gasket but he couldnt fix it. Could that be my problem? If so is it fixable? How much, and where should I take it?