Congrats to two beautiful kids! Its hard to lose kids but don't beat yourself up about it, they could have been stillborn and you could never have done anything in that case anyway. The kids you have are gorgeous!!
Do not blame yourself about the ones you lost. I had one this year showing no signs of kidding, I thought she still had a few days. She was in her stall eating her grain, I walked away to feed the others, heard one loud bleat and walked back to the stall. She was still standing there eating, no pushing, panting or anything else. I started to walk away, heard a *swoosh* and saw a dead baby fall out. If she pushed I didn't see it. She delivered two live does within five minutes of that.
Sometimes even when you are present, there is nothing you can do.