Carrie, not much help I can offer but I do understand a bit what you're going.
The west of Scotland seems to be very poor at dealing with mental health problems. If you're a drug addict or alcoholic there is a lot of help available but as you have found, hardly any for mental illness.
It does seem to be very difficult to get someone sectioned round here, even when they obviously need help. We experienced this a few months ago with the husband of a family member.
In the end he presented himself at the hospital and refused to leave, said he would harm himself right there on their doorstep if they did not admit him.
Unfortunately, as you said, all it really achieved was a lot of monkeying about with his meds BUT the time he was in there for really gave his wife some breathing space and I think that's what you need now.
I have seen first hand how trying to cope with a partner with problems can wear you down and know how exhausted and drained you must be. wanting to lash out is understandable but just puts peoples backs up.
You need to see your gp for your own sake, I think. If he is not sympathetic then ask to see someone else in the practise. This is too much for you - or anybody -to deal with on your own.