"Should you maybe bring someone with you?"" I just shouldn't be going through these things on my own"
"I'm not feeling supported"
" I need to feel held"
"How can I best support you"
"I hear you. I'm listening" (assuming you meant heard instead of held)
Those are my suggestions. Just ask. She may not know what you can do to support her. I don't. EMDR is hard and overwhelms me out then I just put myself to sleep (or just fall asleep on my own) or spend days in dissociation. It's processing memories and moving them around. It's hard. And it overwhelms many and throws many into a spin where they don't know what they need or how best they can be supported. You sound like you are doing all you can. I would ask her then take cues off her. That said, you can't do the impossible either. Learn to give yourself a break too, you know? You are doing way more then most and are likely supporting her even if she doesn't feel like you are. You can feel rather backwards a lot of the time with PTSD.