Sorry midnight star, I didn't see your last post, and the lack of paragraph spaces made my 'advice' illegable practically.
It is really awful to feel like you are not entitled to ask for help when you genuinely need it because of the strange culture of opinion surrounding the issues you are dealing with. All you need to do with the doctor, is (if you feel you need to do this immediately)
1. Not turn up on Monday
2. Follow your usual sickness reporting procedure to let them know you are not coming in and tell them you are going to see the doc
3. Make an ASAP appointment with GP surgery
4. Tell the doctor genuinely what is going on for you
5. Discuss options to help, some doctors are better and some are worse in terms of advice and stuff
6. Specifically tell them that you have not gone into work today, that you can't do your job properly, and you require a sick note, can you have one please
It should be simple, the hard part is actually plucking up the couraging and leanring to be clear and firm with people. If you have problem, you have a problem, if cannot do somehting, you cannot do it, if you need help, you need help. If you do not encounter helpful doctor, make the next appointment with a different GP specifically. If you think you might lose your nerve, or find it difficult to adequately explain, take some one with you(I hope there is someone).