TL:DR

So, given it's a lot to ask people to read, I thought I should write a summary version. For the full version, start at Part 1.

I have probable bipolar disorder (certainly longstanding recurrent depression), and fibromyalgia, which means I am in continual pain to some degree or other, and it affects my ability to walk.  I tried to kill myself recently by overdosing on my mood stabilisers (I took 60 times my regular dose (100mg) of carbamazepine).  I changed my mind about 20 minutes after taking them and told a friend who rung an ambulance.  At hospital they did some tests, including a urine test that stated I had used cannabis in the past 4-5 hours when I hadn't.  My condition worsened while I was there and I lost the ability to walk or speak, I vomited, and I lost consciousness a lot.  Because my motor control and balance were basically gone I repeatedly hit my head (and other parts of my body), including faceplanting from my bed to the floor, and from standing (with assistance) to the floor, and smacking my head off walls.  As far as my friends are aware I was not checked for concussion at any point.  I don't remember much of the period I was in hospital for, bar snippets of memories here and there, but my friends were with me most of the time and have told me what happened.  The crisis team visited me twice and I was unresponsive/unable to communicate both times.  I became delusional and hallucinating (although I don't think anyone realized this at the time).  My friends left because in my confused state I asked them to (inasmuch as I was capable of communicating - very slurred words here and there, not proper sentences), having been told the hospital was admitting me.  The staff changed their mind and decided I was faking, said I was physically and psychologically fine, and tried to discharge me once my friends were gone. I was unable to leave by myself, they construed this as me refusing to leave and called the police.  They *then* rang my friend to come and get me, even though they'd said they would contact them before discharging me.  My friends took me home with the police's help in a riot van, whilst I was still unable to speak properly or walk, and was delusional.  The hospital provided no discharge information or advice or wheelchair, and didn't refer me on to anyone or arrange for anyone to contact me.  My friends looked after me whilst I was drifting in and out of consciousness for the next day, and had to help carry/support me to the bathroom and back because I was still unable to walk/control my body.  By the time I regained my faculties enough to be aware of what was going on I was badly bruised and injured in various ways, including a very bad black eye, and the second eye blacked up over the following day.  A doctor at the local surgery confirmed I was very probably concussed.  I recuperated at home with my friends' assistance, and no input from any medical professionals from this point on.

I intend to make a complaint about this.  Advice would be very welcome, especially from people with experience in making complaints against the NHS.  So far my intention is to speak to the community health council and mind and get advice off them, and request my medical records off the hospital. A friend has also suggested writing to my MP about it.  This happened in a hospital in Wales, if that affects anything.