Fumes

Okay, I am having a huge problem with fumes in my car...It is very hot out so i have to open the window to stay cool...but when I open any window, the fumes overwhelm me..actually giving me a headache...why is it doing this when I open the window?...I cannot determine where the fumes are coming from, but I know that I just had the car safetied, and therefore the exhaust should not be leaking into the car.
surely someone else has had this problem...?

I had the same problem and I replaced the hatch seal it its fine now

There also could be drainplugs missing from the rear wheel wells. On mine, there was a small piece missing from the hatch seal.