I separate my anxiety into two categories: body-anxiety, and regular mental anxiety.
Most of what you described happens to me when its body-anxiety, which means that my blood sugar is low, I'm dehydrated, or I didn't get enough sleep. Anything that can mess with my health can cause that type of anxiety in me. It becomes regular mental anxiety though because I have a health-phobia of sorts. When I feel a bit -off- from the strange thoughts that low blood-sugar or lack of sleep can cause, I can panic at those odd thoughts or sensations and work myself into a full panic attack.
I have learned how to -not- do this.
Firstly I think its worth experimenting a little to see if your health is exacerbating your anxiety. See if eating something helps, think about how much sleep you had.. etc.. You could also get your thyroid checked out. Thyroid problems can cause what seems to be generalized anxiety.
Head types should understand what I call garbage thoughts. Someone once showed me a better term for it, but I can't remember it. This is something that I figured out on my own, then I discussed it with others. I can have a flash go through my mind of something absurd/scary/horrible/silly, but its no more meaningful than the random thoughts that pass through in dreams. For example, I'm sitting there focusing on something, and suddenly I will have a thought arise to jump up, lunge at someone, and stab them in the neck. Now, I don't actually want to, and I know I won't. Its an absurd thought. I had to learn to not worry about those, but rather just brush them off. When I am sleep deprived or have low blood-sugar, they get worse - more frequent, and they are easier to rattle me.
Another issue for the anxious heady types is sometimes
depersonalization/derealization. I read a study that explained how the part of your brain that you're accessing during meditation is the part thats inadvertently accessed during these derealization episodes. When I have one now, I just recognize the physical process, and know it will pass. I don't allow myself to work myself into a fit about it, or the garbage thoughts. I just tell myself whats going on, and I -know- its ok, normal, physical, and will indeed pass.
Not recognizing that is what could make one of these minor things not just startle me, but get my anxiety looping.
Monitoring. That is the term for what we do when we get anxious about the body-anxiety sensations and start paying attention to them. Perfect way to make it worse. 'Oh shit my breathing is weird.. oh now my head feels weird' -- and you can actually feel more physical effects that will begin to feel like a serious problem simply because you 'want' to.
I went into the er once having a panic attack (having a few glasses of water calmed me down this time), but the doc there showed me something. He said "hold out your hand, and extend your finger, look at it. Can you feel your heartbeat in it?" Well of course you can't.. then he told me to -imagine that I could- and sure enough, I could. Though its really not possible. Lol. And thats how this monitoring that people begin to do in anxiety makes them think they have a really serious problem. For example, people usually think a serious panic attack is a heart attack at first. Eventually you learn its not.
Adrenaline. This is the nasty thing that causes a full-on panic attack. Some little thing like a garbage thought, weird physical sensation, derealization - or whatever it may be for you, startles you.. well your adrenaline gets pumping and you become very vigilant. Your senses become sharper, but you aren't focusing this vigilant adrenaline dump on a tiger you're about to kill, in order to know the enemy, and use up the adrenaline in a reasonable way.. the anxious turn it inward. You become afraid of your own body and mind. Oh fuck!
I can not possibly stress the importance of exercise enough for -anyone- who suffers from anxiety. These days we sit in office cubicles and get our adrenaline pumping over our boss's attitude, or the phone call with the significant other.. something horrible we saw online perhaps. The anxious have this anxiety they experience from these little things just build up all day long, and our bodies are just pickled in adrenaline.
Exercise will burn it out, so you will experience less random adrenaline dumps. When a person has a 'random' panic attack, thats what that is. Its your body finally dumping that adrenaline you have been storing up all day. Get some regular exercise and keep it used up. Exercise also produces endorphins which is good for your mood in general.
Alcohol is horrible for someone who suffers from anxiety. It will knock the anxiety out but then it will come back with a roaring vengeance a thousandfold. It basically screws with all of those processes that can create anxious episodes. Very bad.
Stay away from benzodiazepines (xanax, klonopin, atavan. etc..) Unfortunately they work so well, people think, eh, why not keep taking them. Well, they are extremely addictive. If you take them regularly, and people will usually want to after experiencing this wonderful quick fix -- you -will- get addicted. I was addicted to them twice, and w/d from those things can last a year. It is utterly hellish. They can also cause very bad psychological side-effects like agoraphobia, strangely, and a slew of other awful things. Try everything you possibly can before ever swallowing one. Google benzo addiction before you try it too.
I mentioned blood sugar a few times. Eating a healthy balanced diet doesn't seem like something important to most in our culture, when we observe most people around us getting by on mcdonalds every day, but each person has their own unique nutritional needs. You might need to change your diet up a bit. Do some research on what ratios you need. I have known of a lot of people to not eat -too- much, as the american stereotype goes, but I have known a lot of college-aged people to not eat nearly enough -- and yes that can cause anxiety in some people.