Hello
Firstly, the tendency for anxiety sufferers to equate all these weird and wonderful physical sensations as MS is incredibly common. It is well documented by the medical community and if you have a scan over this and other anxiety forums you will find all the empirical evidence to support this you could ever wish to find.
I don't think anybody on here would be irresponsible enough to say that you do not have MS...this is something that only the medical community can do for you
BUT
What we can do is look at your situation with a fresh pair of eyes so to speak. All the sensations you have listed are possible within an anxiety explanation, some are more common than others but you need to realise that anxiety can actually cause pretty much any effect on the body.....I suffer from the spaced out feeling, the buzzing, the twitching, the fatigue, the aches and pains etc etc. I remember for a month over Christmas my back teeth where killing me, I went to the dentist as it was obviously a dental issue...surprise surprise my teeth where fine, about a week later it just stopped...I'm sure that this was just another physical outlet of my anxiety!
What I think has happened in your case is that your anxiety has shifted somewhat...you state that in the past you have had anxiety issues and panic attacks but that now things seem to have become more physical. What this suggests to me is that an accumulation of anxiety has finally had an effect on you nervous system and that your anxiety level has become stuck on overdrive, this exists independently of how you are feeling emotionally now and even though you think that you are not anxious for all intents and purposes your nervous system is stuck in the flight of fight response and misfiring all over the place as a result. You state that you feel that your nervous system feels off , IF YOU WANT TO PUT INTO WORDS WHAT THE PHYSICAL EFFECTS OF ANXIETY FEELS LIKE WHEN IT HAS EFFECTED YOUR NERVOUS SYSTEM THAT IS IT!!!
Wow, your GP is unhelpful, yes all this is related to what is going on in your head but these physical sensations are 100% biologically real....the thing is how they are caused, they are NOT caused by an organic neurological nasty but they are the by product of an accumulation of anxious thoughts and practises and I believe suppressed emotional issues. Where your head really comes into play is how you are monitoring and comprehending these physical sensations....are you just observing, accepting and letting the sensations just go through you or are you worried, scared, interpreting and living in fear of them?? I would hazard a guess it is the latter and if that is the case, congratulations, you are now a fully paid up member of the health anxiety club as the loop is complete and you are dumping more fear and stress on top of an already frazzled nervous system! Of course, all the while this continues your nervous system will NEVER get the time and rest it requires to reset itself.
Like I said at the top of the post, nobody on here can give you a 100% guarantee you do not have MS, even a GP will actually only give you a 99% guarantee if we wish to be pedantic BUT I personally do not THINK you have it. You have to look at the bigger picture. You had a history of resolved twitching, now MS would not really present as twitching and as it was resolved I think this fits an anxiety explanation, you have suffered for the 'traditional' element of anxiety such as panic attacks in the past which confirms a history of anxiety and finally all the new sensations fit an anxiety explanation....all too easily we miss the bigger picture but this is what the GP's look at, an overall history and certainly in your case all the available evidence does point to an anxiety explanation.
If you feel you are being fobbed off by you GP (annoyingly an anxiety/health anxiety 'symptom' in itself) demand a neuro consultation....they will tell you in 15 minutes if any further investigation is required and I bet you that you would walk out of there good to go, it is how you go forward from that point that will determine how all this works out for you.
Hope this info helps in some way, have a look round as there has been a plethora of posts on this very issue at the moment and I always have the opinion we can't all be mad and or ill!
Please also look at the 'have you got 9 minutes' thread in the hypochondria folder and watch the short video, it explains the physical effects of anxiety incredibly well and it could well give you that

moment that we all eventually come across and that helps us through this difficult period.
all the best