Is my head gasket or engine blown?!?! HELP!!!

I have a '94 Honda Accord with 110k miles. I never let it overheat and it has always run great. One cold night I was driving and I noticed the temp gauge was pinned on Hot and my car had only been running a few minutes. The heater wasn't hotter than normal, no steam or smoke from the engine. I drove it a mile and parked it and checked the engine, it was not any warmer than usual, no water boiling. I had to drive it home about 2 miles a few hours later, still registered hot. I noticed no coolant loss. I replaced the temp gauge sending unit and nothing changed. When I start the car cold, the gauge starts climbing about a minute into running and continues to climb to full hot. I thought it might just be the gauge and continued driving it because nothing seemed wrong (my bad!). I've driven it around 150 miles with the temp gauge on hot, but no signs of any problems. After consulting with an auto parts store employee today, he thinks I have a blown head gasket... Is this possible with no driving problems yet? And if so, have I completely ruined my engine by driving it??? Also, I notice after driving it a few miles, the upper radiator hose is hot and very hard, and the lower hose is very cold, almost like it has been sitting overnight. The radiator cap isn't hot either. The fan never runs and the engine light never comes on. Any help is much appreciated! Thanks.

Hot water exits out of the motor through the lower hose, that's where the thermostat is on your motor....it flows vertically through the radiator on back into the motor through the upper....I know, there's a housing that looks like a thermostat in the front of the engine where the upper hose comes in...that's not it though...

If the lower was cold and the upper was hot, no water is exiting the motor. Your thermostat is stuck, or the radiator is hogged up beyond belief...in my '95 which went through a similar episode recently, it was both. VERY rarely it could be something really odd, like a failed water pump impeller that's not moving anything, but that's very rare...

Compounding the problem is the fans usually won't run if there's no circulation....

You need to stop driving it until replacing the thermostat and then checking that there is a normal progression of heat as it warms up, from 'stat housing, through lower hose, radiator warms, upper hose heats up...then you can be sure you have circulation.

Head gasket problem can cause trapped pockets of compression gases in the cooling system that can "vapor lock" the cooling system on some vehicles, but this motor isn't one known for that...usually these are on motors that have bleeder points on the system to begin with because the radiator sits lower than the cooling jacket of the motor...

Not saying it couldn't be, but I doubt it. Usually you'd see constant venting of pressure rolling up through the reservoir return line when the motor was running if this was happening on your engine...the radiator cap on your car is a 14 psi relief, compression to cooling jacket losses will usually exceed this easily, causing venting...there is many times a wet cylinder that will misfire when the motor is started cold, until it clears the coolant out....