MY UPDATE: HEADACHES BEEN GETTING WORSE

I'm 18 yrs old. I have been dealing with Chronic Daily Headache for going on 3 years now.  The headaches began within a week of hurting myself weight lifting (squatting). The doctors have yet to find a cause; all the tests I have taken have come back completely normal (5 MRIs, CAT scan, MRA, MRV, blood work twice, and x-rays). I was on hospital homebound for 2 yrs but now I am starting college and I need to work again, but it is very difficult to function sometimes with my headaches, so I really need to find out what is causing this. I basically have a headache 24/7.. they are worse at times and better at times but they never completely go away. I have severe muscle spasms in the back of my neck and my back (mostly upper and middle) and they are VERY tense all day and achy. I am sensitive to light but not sound. I am dizzy about half of the day. A couple times a day, when I stand up I get a headrush and everything blurs and it's like a black curtain comes down almost all the way down except at the very bottom of my vision, this lasts about 3 seconds then I come back. I never completely pass out but it's really scary. I've been having trouble falling asleep, I get tired but I can't shut my brain off. Lately, I've also been losing my appetite, I get hungry but I don't really feel like eating. I've been getting anxious and sad the last 2 months or so, but I think it's because this has just been going on for so long, and the almost blacking out a couple times a day is really scaring me! I've been to a bunch of doctors (eye doctor, neurologists, chiropractors, had acupuncture a couple times, and I have been tried on a million medications) and still no answers. Any suggestions? I really need some help..