Hi ch , We want to welcome you here to neurotalks t.n. forum tho sorry it is for this type of pain.
you mentioned your eyes and your sight being affected so perhaps you may want to post this in the O.N . (Occipital Neuralgia) forum also here is the link...
http://neurotalk.psychcentral.com/thread139769.html
many of the things you described do sound like t.n. ie... the pressure sensitivity to hot and cold , the face pain etc.. all sound like a type of t.n. to me.

I AM NOT A DOCTOR OR A PRO in the least bit of way , so it would be best to get in to see a neuro or pain doctor if at all possible.
I do know sinus infection can cause t.n. as the infection if not treated and taken care of can travel from the sinus to the trig and other nerves in the face and head. I think having the flu and still feeling this a couple months later does not seem right. I for sure would find an different doc then the one you have been seeing ..a neuro if you can . you need a second opinion and better answers then this is left over from a flu... and a remedy to all the issues you are dealing with. I am sorry you feel rotten and hopeless but all of us have been or are feeling much like you that is why this place is a comfort ..WE ALL UNDERSTAND AND GET IT.
I would not go route of a dentist and have a bunch of teeth work done unless the dentist can show with x rays and such the need to pull or have teeth work done. MANY have had lots and lots of dental work done in hope of fixing t.n. pain only to find none of it was necessary and the work made the t n pain worse .
there are plenty of options for dealing with t.n. and o.n. pain ... nerve blocks work, botox injections many kinds of meds .


for starters cover your head, ears when you go outside that will lessen the triggers that wake up the pain monster. maybe just soaking your hair and wash that way instead of a shower that blasting water on you or try those caps where you dont have to even use water to wash your hair. my elderly mom used them before she passed away. allot of hospitals use/have them
please take things day by day look for another doctor a neuro if possible and dont give up hope.. hope is why we are all here hope is what we try to give each other every day and HOPE IS out there !!! sometimes you have to tell the doctors and not just let the doctors tell you and then push you aside you have to roar and be the squeaky wheel. if this is all left over from the flu then DO SOMETHING cus it is NOT going away its gaining control and you are the Doc so either help or send me to a professional that can. that is what I would be saying. i am really sorry you are dealing with all this. please let us here know how we can help or any ??? you may have just post someone will reply. and know that all of us have you in our positive thoughts and prayers. Hope you keep us informed on how you are doing and how things go. your our new sister now
low pain wishes and giant hope for a remedy or answers for you!!
PEACE
BMW