I'm sure R can post those to you.
I don't know what to say. It must be horrible, being away from her. I'm in the same situation myself right now (just arrived at my new school in hungary and talking to my love on skype, trying not to cry and failing miserably). It's lonely and sad and awful and all you want to do is go to bed for the rest of your life, if you can't be with them.
It sounds like you've been really proactive in making your plans. Definitely organise the visits you mentioned and try to get there to stay for good as soon as possible. Having something to look forward to will help. And remember, you're just home - it's going to be more acute when the memory of her is so fresh. You'll get back into a routine with college and your cool job and it'll be easier.
I think if you can think of ways to limit the time you have to spend with your mother, it would help. If she only hurts you then you need to be away from her some more. Incredibly difficult I know. Are there friends you could stay with sometimes, also as somewhere to go during the day? If you can think of time you spend with her as finite, it might be easier to take.
And remember, despite all these hard and sad things, you're very lucky, because you have R. So many people never find real love and here you are at 18! All of this is just a blip on the road, sweetie. One day you'll be together all the time and it'll all have been worthwhile xxx
'I had made the mistake of powering up my consciousness without having the appropriate scaffolding in place'
Marni Jackson, 'Pain'