Hello
This is my first post on the forum and I read with understanding your frustration and hurt that this aggression is becoming worse and is not understood. Just before Xmas last year, we took in a beautiful golden cocker spaniel who had lived in kennels for 4 months due to her owner going into a hospice. We understand that she will be 3 in August and I must admit that her behaviour has gradually improved. She is still possessive over her food, even if she smells it and doesn't want to eat it yet, she will lie down next to it, at first growling deeply and viciously if you even go into the kitchen. She is not allowed to have any toys or bones etc. as she is possessive over these too, so we have learnt not to put her in that position in the first place. She used to growl terribly at my 11 year old son for no reason and again, this has gradually got better although if she is on our bed and he gets on, she will just move away and we then understand that she does not want to be bothered with him, but at other times she goes to him and licks him affectionately.
I agree with the others though - why is this dog so highly strung at only 6 months? Sound advice has been given that you need to totally ignore the negative behaviour and praise the good. No eye contact, talking or anything and let the dog come to you as and when ready. Also a good idea to delve deeper into any possible health issues. Another thing to think about is your apprehension - is this being picked up and making matters worse?