Is all this pain and weakness really from anxiety!?

Hi, first time here! Basically I was a healthy 20 year old female, studying at university, frequently exercising and working a job. However, I've just not been right for around four to five months now. It all started with small bouts of what I know realize were little panic attacks (feeling hot, faint, loss of breath, closed throat, generally feeling weird as though the walls were closing in on me). This has progressed to the point where I am permanently anxious and on pins, people have even started to notice and I've had comments and questions 'are you always so wired?', 'Why are you so twitchy?'. This seems to get worse and worse day by day. The main thing which is worrying me is that around four weeks ago (assignment time) I began to get very weak feeling, twitchy and shaky legs and also had bouts of shaking during the night, where I would wake up normal temperature yet feel incredibly cold and literally dither for 20mins plus. This has now progressed and two weeks ago I began getting tingles in my legs, feeling the need to urinate 24/7 and the weakness persisted on and off. Within the last week and a half though, everything seems to have gone 10 times worse! I had terrible back pains (lower) and then started struggling with one of my legs (siatica trouble I believe) which has been hitting me on and off every couple of days. Though, it has been ok for a couple of days now, the pain has moved up my spine and now the top hurts and I keep getting an incredibly stiff neck on and off throughout the day, again with bouts of shaking. For the past two days literally everywhere hurts to touch, my back, bad pains down my legs (especially thighs) arms, neck etc. and I even have pains under my arms (with no swollen glands). I visited a doc last week and she though most of it was due to anxiety and gave me a three day course of anti-bi's for a small UTI but when the back pain became worse I ended up having to go back and see a different doctor a few days later who checked my reflexes (which he said where 'impressive' so I don't see any problem there) but he seemed to be more concerned about my lower back pain (I didn't explain everything I think he'd have boxed me off as a sever hypochondriac). He thought it may perhaps be degenerative disc problems so has given me meds to take but I've been looking up my symptoms online (a big no-no I know :/) and lots has been coming up about spinal tumors so I am ridiculously worried (even though at times I know its pretty irrational to jump to that conclusion)! All week I have had no appetite and have had spells of feeling very nauseous on and off, which usually comes after the shaking and my IBS had been really bad, I've been straining on the loo so much my legs and back hurt but I've only managed to go a very small amount. Today I've been much more relaxed and despite feeling sick in work (I'm thinking due to no breakfast) the pains are much less, though everywhere still aches to touch. Could it really be anxiety causing all of this, it seems to be a vicious circle, I panic, I hurt more, I panic more! Any help or similar problems anyone has had would be much appreciated, I've not really spoken to anyone about it all and I hate going the docs! Thanks, Sofia.