Intake manifold or head gasket?

I have a 1998 Ford F-150 v6 4.2L w/112000 miles on it and the other day i was coming home from work when i noticed the trucke wanting to die when i would slow down to turn. When i accelerated it was real sluggish and didnt want to go then finally it kicked in and took off. It did this all the way home till finally(thank god) as i was pulling in my driveway it died. I popped the hood and some steam or smoke, it looked like steam was seaping out from the righside firewall and from my air filter. Also i noticed the coolant resevoir bubbling. So i took the oil cap off and at the tip of the cap was some milky oil, also checked the dipstick and same on the end of it. Is it a blown head gasket or what. Thamks for the advice.