Hi Marnie - Let's see if I can share about some of what you mentioned.
A healthy house is something to consider. I personally try to keep the chemicals down to a minimum in my house. There are things that are actually toxic and can cause headaches and problems. When I saw your question I felt it couldn't be answered simply, so rather than type it here, we made a new page on our site concerning allergies, environmental illness and having a healthy house. Actually, it's still being modified but everything you need should be there. I'll be posting some other links to other good resources & websites though in the next couple of days. I'll post the link below.
Concerning TMJ, you may want to do a search on a TMJ device called NTI. This helped me more than the normal splints. It also sounds as if you need your eyes checked. Eye strain can cause headaches.
Stevia is a good product - but it actaully bothers me and additionally I don't really like it. Most folks do well with it though. Good luck with that!
I really don't know what's going on with the congestion thing when you are hungry. If it were me, I'd do the colon cleansing/ parasite cleansing/ Liver Flush thing (please research this well before doing this as there is some bit of risk involved), and then work on the gut rebuilding thing. However, I honestly don't know if this will address your issue, since I don't know what's really going on. Anyone else out there want to guess?
As for the anxiety, I really suggest you get yourself checked out medically to put your mind at ease and to rule out anything serious. I know it can suck to go to the doctor and get the tests, but maybe you need the peace of mind. We also talk about the mind/spirit/body connection on our site (I'll put the link below), and anxiety in itself is enough to create headaches.