Keep going, you are doing brilliantly! It took my DS (2.1) about 5 days of learning to settle himself then he was fine, only asked for it for another day or two after that
Half an hour crying is not too bad and you did well to be so strong and not give in, especially at night and if you are ill. Next time (if there is a next time) he won't cry for anywhere near as long so you are definitely doing the right thing.
The other day my DS was crying in his cot 'dummy dummy!' and I went in to explain he's a big boy now etc, but it turned out he was saying 'tummy tummy!' he wanted me to turn him to lie on his tummy! I think basically they adapt to not having a dummy very quickly - a lot quicker than we do - and a lot of the dummy dependence is in our heads as parents.
Don't cave in. You are through the worst of it and very nearly out the other side. By this weekend the dummy will be a distant memory!
God, I so, so sympathise and am sending HUGE good luck wishes to you. We have not yet tried to take DS's dummies away (he is 2.2) but he loves them in a deep, deep way, talks through 'em etc, draws such comfort from them -- just as you say about your DS. I know it will be really tough and time is ticking on, we must do it soon. <worries>