I hate the rollercoaster emotions. I get like that sometimes too. It's worse than being just straight up depressed. Everytime you get up you think woohoo, this is it, I've made it, and then here's comes anohter down. It's very exhausting.
I agree that journaling can take to much energy sometimes. Have you found anything that helps when you're feeling low? My t made me sit down and make a list with things that help me, so I can go through it when I'm down. I actually found a bunch.
My main go-to pick me up is baking something. It's so calming.

I hope you can get the help you want and need soon.