Toxic Fumes in Car - help

[svxthc]

I'm driving and smell almost odorless fumes coming from the engine. I checked the oil level/psteering level and all is good. On my way on an 800 mile drive I smelled something and found out I was low about 2 quarts of oil. Fixed that.

Now I'm about 1 quart overfilled. Is this bad? I accidently spilled a little oil outside the oil chute because I had no funnel, could this be attributing to the smell 3 days later?

Tonight I had a headache and I'm not driving the car anymore until I take it to jiffy lube or some dealer. The temp gauge was always fine, even when I had low oil...weird. Power on the freeway seems to fluctuate and today the tranny seemed to be shifting a little hard.

Is this a tranny omen and what is that smell? I didn't have the vents on or AC and had all the windows down.

PS- I can almost tell you for a fact its carbon monoxide just by the quick symptoms I felt while driving and afterwards. I'm kind of scared to drive it to jiffy lube without a gas mask.

Also, I want to say that I had the exhaust manifold underneath the car in front of the muffler removed as it was bad. Could this also be part of my problem?