6m old no sleep -save me

[charlottero]

My 6m old just cannot sleep through the night. Not even close. She NEVER has. The best night I've ever had is 2hourly wakes and the worst 10/20 minute wakes.
I've done the sleep courses and feel like I've tried EVERYTHING. We have moved her to her own room now in the hope that things might change. I completely did my back in by simply getting up so much in the night and being with her all day.
In the day time I laugh with people about how awful it is but at night I am honestly suicidal. My husband is really helpful, but even when he does half the night we are still both up. It takes me so long to fall asleep because I just feel like she's about to wake up (and usually does.)
Things I can think of that I've tried (for weeks, if not months...)
-routine bath etc
-pitch black room
-formula night feeds
-white noise
-good day naps
-sleeping bags,swaddles,sleepyheads.
-dummy
-feeding to sleep/not feeding to sleep
-big cot/little cot
-early bedtime/late bedtime

I don't know if I even can be helped or just comfort in that someone else has the same?
I am genuinely at the end how can anyone possibly go on with 2hours sleep a night for 6 months.

Could you and your dh do a night each so you have a full nights sleep every second night?
Do you have a spare room to sleep in?
Does the baby take a dummy?
Is the baby fully crying when they wake?
Are they definitely warm enough? Mine have always liked to be on the warmer side than is recommended.
I'd do sleep training if it was this bad personally. There are gentle methods.

If she's only having 3 x 30 minute naps then she'll be overtired which won't help nighttime sleep. It also sounds like she can't link sleep cycles.
Put her for her naps in her cot in the dark each time with her sleeping bag on, then stay in the room and watch her. Just before the 30 minute mark she will probably start to stir. Before she wakes, gently soothe her back over into the next sleep cycle. Do this for a few days so she's not so over tired.
Next work on putting her down awake to soothe herself to sleep. You can do this very gently, babies take 10 mins to fall asleep after their eyes closed (20 to go into deep sleep), put her down as soon as her eyes close at first and then pat her, shh her (whatever works). If she wakes and cries then pick her up again then just keep trying the same thing until you can eventually put her down drowsy but awake.
This won't work if she's overtired though so you need to work on lengthening those naps for a few days first.
If she's waking in the night for her dummy and that's the problem then I'd just bin it now or teach her how to put it back in herself by doing this-
For naps place the dummy in her hand and guide it into her mouth. Do this for a few days. Then just place the dummy in her hand and hopefully she'll have got the hang of putting it in (if not, repeat step 1 for a few more days).
Once she can put it in herself try putting it on the cot next to her and tapping the mattress next to it to show her where it is (scatter several glow in the dark ones so she can see them). Repeat step 2 for a few more days if she can't pick it up and put it in yet.