Yaris has low power and won't start

[FellFromGrace]

Hey everyone, my names Christina and I'm new here.
My Yaris has been down for a while now... Been trying to figure it out, but haven't had any luck.
It's an 07' and manual.

The problem just kind of happened out of no where, so I can't give any information regarding symptoms it was having before the actual issue.... I can try and shed some light on what I'm experiencing now.

Woke up one morning, tried to start it. Nothing. It doesn't turn over. Tried jumping and changing batteries. Still nothing.
Some of the small dash lights like the Check Engine Light illuminate, but not the actual speedometer/clock etc.
The interior dome light is dim, and sometimes not even on.
No headlights. The very little dash lights that do illuminate cut out when I apply the brake and slowly come back on after I let off.
I checked all the fuses under the hood, all good. I even tried bypassing the clutch safety switch. Stilll nothing...
Even tried ODB, but it doesn't even seem to have enough power to do that.
Just keeps trying to connect.

I'm very lost...