Troubleshooting for blown head gasket or engine cooler

Been adding coolant for around 3 or 4 months but wasn't leaving a puddle underneath vehicle. Would occasionally notice a drip of oil or 2 underneath vehicle nothing huge. Suddenly there was a big puddle of tan colored oil with coolant under the oil puddle. Pulled dipstick and it had oil covering it top to bottom. The oil appears to be unusually thin. Most of the underbody appears covered with tan colored oil. The vehicle also has a code for misfire in cylinder 5. The temperature gauge will go over to hot and usually would go only to halfway point. Since noticing the oil/coolant puddle, there's a constant drip underneath the vehicle closer to the passenger side. Does that sound like the head gasket, and will head gasket sealant be still likely to work? Would rather not invest in replacing the gasket if there's a chance the sealant will work. Would it be worth at least trying the sealant? Then if it doesn't work still be able to replace the gasket. Would appreciate any sound advice.