Rep Power: 0

Was driving the interstate yesterday and it sound/felt like my headgasket or belts blew off. Car shut down and crept to a halt. Tried cracking it over on the side of the interstate, and it was trying to turn over but wouldnt. So I was thinking it was the belt. Had it towed last night and when I opened the hood, belt were still there, and my oil wasn't milky. This morning a turned the key to see what I was working with and it sounded like a piston was fighting UFC with the others inside the engine. But it did turn over. I haven't opened it up yet thought I would ask y'all first. What could be wrong with my car?