Thanks for all the advice everyone, I'm feeling a bit less useless now :)
Hunnypieprank - I'd been having slightly strange muscle aches and pains for a while, but because I'm 47 and have been having a few perimenopause symptoms, I wrote it off as just another one. Then it got much, much worse one evening to the point where I was throwing up with the pain, saw my GP at about 5.30pm who said he thought it might be my gallbladder, gave me an injection of buscopan to try and relieve the pain, but said if it hadn't worked in about 40 minutes to head east to our nearest A&E, which is about an hour away (I live in a remote part of the Highlands). Got admitted to hospital and put on morphine at 10pm that night, the next day they decided I was too ill for them to handle and sent me on a two-and-a-half hour transfer in an ambulance to the main hospital for the Highlands in Inverness, where I got put straight into the high dependency unit. I don't remember very much about it, but they told me afterwards it was pretty touch and go for the first couple of days - I remember my hands, face and feet being permanently pins and needles, my blood pressure being so low they put an arterial line in to monitor it constantly, they were worried my heart was going to stop, and at one point my brain started randomly processing everything from my right eye at 90 degrees to the left eye.
I don't drink, so as I slowly got better there was a 2-week argument over whether a small 2mm blob they could see on the ultrasound and CT was a polyp or a gallstone. I went onto nil by mouth twice in anticipation of having my gallbladder out, only for it to get cancelled because someone thought to ask me if my stomach was usually the size it was and on finding out that I was about four dress sizes up from normal decided to delay until the full gastric team was in and then my consultant cancelled it completely on the grounds that keyhole surgery on someone with that much abdominal fluid (it had gone down - when I arrived there was so much that there wasn't space for my lungs to inflate fully) invariably got extremely messy and ordered an MRI scan and another CT instead. The scans showed I definitely had a polyp and no sign of any gallstones, nor had my pancreas necrotised or grown an abscess, both of which they were worried about because my platelet count was still sky high. The cause has been put down to a ridiculously high triglyceride count - normal is 2.7, very high is 5, mine was 55...my blood was so full of fat that they couldn't do a lot of the normal tests on it! When I'm better they want me to go and have some testing to try and figure out why, there's a gene mutation that can cause this apparently and they want to see if I have it.
CopperMaran - thank you, I was seeing a very good counsellor early last year for some issues I wanted to deal with and I'm seriously considering booking a catch-up session with her to talk about all this. I think I'm okay, but it's all still a bit recent and I suspect it may whack me in the chops a bit further down the line.