Anxiety and Stress?

Happy Holidays, Everyone -

I'm feeling blue as of late and was hoping to get some opinions from you. I've been to many doctors who have run just about every blood tests but can't seem to come up with an answer. The only test that ever came back elevated was my parathyroid (NOT thyroid - that's always normal) but calcium was normal. Anyway, here's my question: have any of you experienced physical effects from anxiety and stress? Truly, I don't feel stressed - I only feel bad because of all of my symptoms, which include hair loss, weight loss (can't gain weight!), headaches, etc... It's these symptoms that have caused my worry. I'm in my 30s and expect this is how I should feel in my 80s! Like I said, I've had just about every medical test done and the doctors say I am fine. I'm just wondering if anxiety and stress can cause such extreme physical symptoms. Has anyone had any experiences they could share? I feel awful and don't know who to turn to. Any help or advice you can give is appreciated. Wishing all of you all the joys of the holiday season and a happy and healthy 2012. Be well.