Can Exercise trigger anxiety, nausea and chronic headache?

I was experiencing mild headaches with some moderate sleeping issues for several months.  I have no significant medical history, am male and in late 30s and physically fit. I do not take any medications.  I've never had sleeping trouble until recent months.  Since I was 30, I've had experiences with migraine which would start with aura then manifest into full blown headache on left or right side within an hour, only occurring after exercise, but no pattern as to how much strenuous activity triggered them.  As recent as 3 months ago, I was getting migraines at work and home, fairly randomly, perhaps 3 times a month.  So I started working out religiously 3 days/week and so it seemed, the random migraines at work and home, as well as exercise headaches stopped for a couple of months.  However,  After a vigorous workout last week with much sweating, on my last exercise I was doing squats on a weight training machine and pushed a little too hard. After that I felt dizzy, tired and was having nervous symptoms. The following day after not getting sleep I experienced larger headaches and continuing nervous symptoms. The day after I was getting feelings of anxiety with headache, nausea then loss of appetite. I went to the ER the next day, and luckily MRI and CT were clear as well as heart rate and blood tests. I did not have EKG, surmising that blood pressure tests ruled out any heart issues.  However, symptoms still persist.  It's been about 7 days now.  I have nausea, headaches, anxiety, trembling and have to force myself to eat.  The headache travels from a band above my ears to the back of my upper neck area and vice versa and can hover in any of those areas for some time, but mostly resides in a band around the ears with some ringing  It seems the anxiety symptoms occur stronger when the headache is in the neck region.   My neck gets tight as well as jaw areas when headache is around the neck.  The anxiety symptoms have subsided slightly the last couple of days but last night I had what felt like a 'panic attack'.  I have tried taking Kava Kava, Tylenol PM and Magnesium to help reduce the headache and promote relaxation as well as sleep and has small benefits.  I cannot get rid of the headaches, however.  I have not been back to work and am concerned since I cannot focus.  It took much effort to write this.  I have seen PCP and specialists that want to treat symptoms with drugs and no further proper diagnosis, dismissing it as general anxiety, cluster headaches or chronic migraine.  I don't believe this, I think there is something more.   I refuse to take drugs that are labeled with side effects causing more potential harm. What is happening to me and what can I do?