engine overheating

I was accelerating to overtake and I heard a thump. A few miles down my engine was overheating. I let it cool and I noticed a clamp on a return hose at the back of the engine had somehow come off and all the coolant had spilled out. I bought a clamp and reattached the hose. That's when things got worse. Now it seems my engine gets hot, all the hoses for coolant get hot and coolant overflows from the overflow hose. My fan works but it seems it only kicks in after the coolant has overflowed.I'd there some kind of blockage?

I have a 3.4 liter