Basically, most if not all symptoms can point to other diagnoses, and all together, those symptoms actually sound like a general alarm call for 'something's not quite right and my body's working hard to compensate'.
I have all your symptoms and have a connective tissue disorder, too low blood pressure (that also shoots up high on occasion just to be annoying), and bad migraines. I also had hyperparathyroidism as well which really affected my whole functioning. That got solved easily (a mini capsule once a week and blood tests to monitor progress, so nothing scary, although it took a good few months to restore the hormone balance again. I noticed a significant difference after, and realised how hard it is to function when something in your body is out of kilter.
It's the brain fog that's I find difficult to deal with, but as I know what causes it I can work at avoiding the fog descending rather than trying to work through it (which is super hard and leaves you feeling utterly drained and demoralised).
Migraines are another thing that cause very scary symptoms. I thought I might have MS, or be having a stroke as I couldn't speak properly (got most of the right words
but in the wrong order no matter how hard I tried, horrible to experience), my mouth drooped down on one side, and my right side got very clumsy and droopy. I couldn't see properly, move properly, short term memory went, and that's on top of the classic migraine symptoms of head ache, vomiting, aura/ flashing lights, and light phobia. I saw a neurologist yesterday for the migraines actually, and he's got so many different medicines I could try (my GP gave me the impression that if the usual 1-2 medicines didn't work that is just have to live with it), and I'm also on the waiting list for Botox! Apparently it can be life changing for some people... If only he'd do a few more on my face 
Obviously, no one can diagnose you online, but just reading through all the things it could be might be somewhat reassuring? So, not to start you off worrying that instead of one scary illness you now have ten to worry about, but thinking that it really could be anything... And most of the things being mentioned are either curable or manageable.
As an aside, there is a type of migraine which can happen without the headache, so often people don't know that they have migraines... Remove the main symptom and suddenly, migraines become very scary indeed, as the symptoms are so wide, neurological in type and well, just bloody scary if you don't know what's going on.
Just food for thought 

