FightingEstrangement, I feel for you and your mum, as well. I think it's great that you were able to give us some idea of both sides of the issue - that's something we don't usually get on boards like these.
If I may, in your mum's defense, she probably ignored you when you misbehaved as a child because that was the only effective method of discipline she knew. Doing it for days at a time was way over the top though. I am so sorry about that. (((Hugs)))
Now it's a habit, I suppose. I bet she deals like that with everyone right?
Since much of your relationship with her is good, I would say try to keep it going. But you're finding it "exhausting," so that's a different story. imo. Could you find other childcare? Fill your lives with other activities, etc. so that when she pulls away for you for weeks at a time, perhaps you won't feel it as much? Then you can be freer to say and do as you please (not rude, of course) without worrying so much about offending her. Then whetehr you see each other or not and how often will be all on her. Think about it.
If you have a tendency to be rude or know-it-all (some young parents are, I find), and that's what offends her, then please try to curb that behavior. It may take a while, but it will be worth it in the end if it helps your relationship with her.