First i would look where the air is coming into the rooom, maybe i could break through it.
If not i would search the walls and floor for some kind of switch.
(to open one of the walls if theres a passage ^^)
First, i'd probably freak out entirely. And after i calmed myself, i would probably search the room after something useful. I f there was none. I would probably fap, take a dump in the corner or something and hope that dying from dehydration isn't as bad as I've heard.
Start feeling around, Start knocking the walls/floor/ceiling (If I can reach the celing that is), Whatever sides the softest or makes any sort of noise start hammering away at with my fists.
Rest in a corner (Keep my ears open) and repeat the cycle untill im free.
Find the opening in the room that is allowing the oxygen to enter, proceed to have intercourse with it, then fall asleep. When I next awake, I will find that my disgusted kidnappers have put me back in my home. Upon inspecting the refrigerator, I will find that all my food is gone.
I can hold off eating for 2-3 days before I pass out I even proved the "you can live w/o eating for a week" thing provided i had water and tons of sleep. so when that happens I'll sleep swallow saliva and eat my clothes, when i need to and just find a way to escape. if all that fails i'll die