Esa assessment but in support group?

Out of the blue I received the dreaded white envelope to go for ESA assessment, last one was in October 17 and I was put in the support group. I thought under the new guidelines I wouldn't be reassessed, clearly I was wrong.
As last time the assessment considerably damaged my physical and mental health, I'm going to complain about this. I've got fibromyalgia, I believe my circumstances fit the four categories, I'm never going to get better. My health has actually deteriorated since the last assessment, I've currently got four referrals for hospital treatment on going!
I'm going to do a letter of complaint today regarding being called for an assessment despite being in support group and I'm sending a copy to my MP.
I have very high blood pressure currently uncontrolled by medication and because my anxiety last time was off the scale my GP will have to give me valium to attend this one.
Having to discuss my circumstances causes severe depression and anxiety, it took me weeks last time to recover.
I'd appreciate any help and guidance anyone can offer. Of course this assessment will be an attempt to get me out of the support group but I'm going to fight it all the way.

Yes I did and I used the guide to fill it in, I didn't hear anything for 4 months so thought it was ok, then the f2f.
Since I filled the form in my health has worsened. Fortunately I've got a new GP and she's great. Instead of fobbing me off every time I get a new symptom, saying oh it's just your fibromyalgia, she's actually listening to me and referring me to hospital.
I've been diagnosed with arthritis in my right hand and waiting for a splint and steroid injection.
I've been struggling for some time with incontinence, again told this was my fibromyalgia, she's now tested my urine and I had bad infection and blood in my urine so referred to a urologist.
I had a brain scan because of severe migraine, ear pain, tinnitus and dizziness. Got results which shows cause but unfortunately no treatment possible.
Finally she's encouraged me to deal with my anxiety and depression and I've had counselling and currently attending a pain management course.
This has all happened in last 6 months so isn't on the form (apart from brain scan) I've rang today and been advised to send in details of above to the assessment office, which I will do, but am I right in thinking as well as giving the factual information I need to stress how each condition affects my daily life?

Ok I've filled in a new ESA50 updated to include latest info and conditions. I've printed it out and tomorrow I'm getting copies done.
Ill hand one into assessment centre and send one to the dwp office dealing with my claim and ill take two copies to the assessment, one to give assessor and one for my helper to go through.
Ill include all my referrals etc but my gp has not got anything confirming diagnosis of arthritis yet so need to chase with hospital.
My GP will give me diazepam to help with the anxiety of the assessment but I've been advised that I shouldn't take it as then they won't see my full anxiety. If I don't take it ill be a mess, I was last time and it made me really ill for days afterwards.
Thank you very much for all your advice it helps so much. I tend to go into panic mode and then can't think straight. For example got a letter today to ring to book gastroscopy rang hospital booked appt for a time I can't go and forgot to ask about sedation! My mind just fogs up and I lose it.