I may be out of line but I'm surprised that this is the first time you're allergies are showing up for this kind of 'stuff'. What I mean to say is: If it's happened in the past (maybe not in your home) with similiar products like paint, household cleaners, new-car-smell, etc., , didn't you see this coming? But in your defense, if the contractor said the fumes would be gone in a few days and your health should be OK, then maybe either you didn't impress upon him the severity of your allergy, or if you did, he didn't get that impression. And, he's not a doctor (who was someone you want to call NEXT time you're in a similiar situation.)
In any event, for the average Joe (which you're not because of the allergies), the odor subsides after 4-5 days. The can of poly does say to make sure there's good ventilation which you say you have had. The fumes are known to be harsh on some infants, senior citizens, or those like you with respiratory problems. Even if you said something to the contractor about your allergies to such fumes, you probably should have gone with water-based poly anyway. It's not worth subjecting yourself to such conditions especially when your health is involved. (I know this doesn't help you but it may help others in a similiar situation down the road.)
All I can suggest is that you don't put anything in the rooms until your health returns. Area rugs, furniture, and such tend to 'withold' the fumes longer, and absorbe them, because they prevent circulation. It may be wise to ventilate the room below the finished room (if you have a basement or something) too since it will help. As far as where to write or call about complaints for toxic chemicals, you may have a hard time finding a sympathetic ear. Oil-based poly is not a banned substance. Its DISPOSAL and USE, however, is. It's use in certain circumstances could break the law. Such might be the case where you see someone using it to, say, seal up their boat-hulls. (Marine varnish is used; the poly will break down, come off, and pollute the water. This is worth complaining about if you know SOMEONE did, or is doing, this.) I wish I could say more.