Mine were sleep trained DD at 14mo and DS at 9mo. I don't regret anything about it except for waiting as long as we did. I was hallucinating with tiredness with DD, couldn't drive, didn't feel safe being around her. And yes, I was close to hurting myself over it. I couldn't go through that again with DS, so we did it a lot earlier.
They were both utterly miserable because they were exhausted. DD especially, and then when DS wouldn't sleep she was kept awake again (she was 4), so I said it had to stop.
We left them both for 1min, then 2, then 3, etc, going in to comfort (but not pick up!) between each time. Our cut-off was 10mins (which we were planning to repeat) but it never got that far. I think the longest was about 5mins before they fell asleep. First nights were awful, second was worse, third improved massively and by the fourth they were sleeping through. The change in their temprements was immediate, it was like a bloody miracle. Who knew that waking up every 30-45mins and having to be helped back to sleep by someone who was losing their mind would make anybody grumpy during the day?
It doesn't work for everyone but it worked for us. They're 7 and 11 now, and neither remember any of it. Both go to bed without any battles, and sleep perfectly. All of the stuff about "they learn you won't come when they cry" is absolutely fucking bollocks. If they need us, they call us. If they don't need us, they sleep.
Good luck to you, OP. It's rough, but you'll get through it.