I dont have a situation even really that close to yours but thought I would say I hope things do get better for you and that this new chaptet is super positive.
I do understand some of it though. The emptiness but maybe mine is different. I have a family and only work a few days a week. My H and children are the only people I have and I even come close to losing them. I definitely have suffered more from depression in my life so I dont know the most of the time manic part. My manic episodes are normally quite short lived like a week to a month and arent pretty, productive things for more than a couple of days.
I think my emptiness is the feeling that I need to do more, I need to be me more. I am missing a part of me but its not people, its who I am. The more mania I have the more I find myself and then euthymia seems dead though. Do you know who you are and what you want? Then focus all the energy that you can into those things.
The things I hear you saying are that you are lonely and tired of the mad rush leaving everything(people,hobbies,ideas etc) in the dust behind you. Correct me if Im wrong though, stupid internet disconnect makes it hard.
If I am right the best thing I can think of for you is figuring out a way to slow things down so everything else can catch up. Are you on meds and do you think they are best ones for you at this point? The only other thing I can say is my shadow is the only thing that can keep up with me when I am up. That isnt advice lol just something that keeps me from feeling lonely when there are no friends and my family has fallen too far behind.
Sorry if this was useless. Too quiet here, now back to drinking and dancing