Hi there.
I'm not in your situation but very much recognise the signs of someone who is really on the edge, I got to that state of mind when I was looking after my daughter. My point of view might be at odds with some of the others but I can only say what I feel, no more or less.
I am very very glad you have got the respite coming up but I don't think it is going to be enough for you. I only had one weeks respite from my daughter in 21 years and although it was wonderful, I'm not really a believer in the "re-charging" of batteries as you are right back into the same routine after respite and nothing has changed. For respite to be effective it has to be regular, long enough so that you can have time to help yourself..counselling, something specific that you enjoy, something along those lines.
I am inclined to agree with Scally (although not with the sentiments that Flossie pulled him up about!), I think for you to continue like this is dangerous. Something has got to give and it will probably be you. Some of us are at our wits end and we somehow continue to carry out our caring role but for others it is just not possible to cope anymore..I think you are the latter Blue.
This is not a judgement on your abilities, just fact and you have nothing but admiration from me for how you have managed to cope with this situation until now but also for your honesty.
You have shared some very personal stuff with us, including the depth of your feelings towards your mother. She may be your mum but she is making your life hell, you are in danger of losing your grip completely, possibly losing your temper completely and you just can't carry on like this.
You're a brave man and a kind son because you are still there after all that has happened in your life. You have decided to start the process of ceasing to deal with the effects of your mothers dementia and I totally think you have done the right thing.
I am also on Citalopram (even though I'm a tough cookie!!) and it has been a massive help for me. I'm on 30mg, a dose titrated by myself with my GP's input and have been on them for about 8 months, primarily for very high anxiety levels and depression. I also used to get panic attacks. I think the key for anti-depressants is to use them not as a cure, but as a stepping stone to help you through a rough time. Too many people expect them to work miracles but they can only help if you are pro-active too. Writing on here is being pro-active, doing stuff to help your transition from carer to free person is helpful too. can I suggest that you also give the counselling a go? Maybe some time set aside for specific relaxation, maybe getting support from a local carers centre..there are lots of things you can do.
Don't be frightened off by the leaflet that comes with the meds, it can happen but it doesn't mean it WILL happen! 10mg is a very low dose, you may need something a little stronger and funnily enough I found it better to take mine in the evening so I didn't have the muzzy head.
This is just the start of you taking your life back and there is nothing wrong with that, nothing to feel guilty about.
Keep us posted
Even the poor dogs are looking at me and running .. 
