Aw, linedancequeen, big hugs to you
I'm so sorry you didn't get to hear pink, I do think the various gender prediction things are often wrong and all they do is raise hopes, which then really, really hurts if the dream does not come true. How you are feeling is very natural though, I think its great that you can already see that you will love your little man, and that is what I hold onto - I have come through GD before and even though I know how much it hurts, I also know that I can come through it again.
As to your mum, well really I don't know what to say My mother is totally uninterested in my 2 boys too, I know how hurtful it is. I don't have any blood nephews or nieces though so fortunately I don't have the added pain of her taking an interest in one of my brothers' kids but not mine. I honestly think treating a grandchild in a really obviously preferential way is just as bad as when its your own child. Kids are not stupid, they pick up on this stuff very very quickly. It is her problem and her loss though, you know the value of your beautiful baby boys
I really hope you start to feel better about things too - your family will be very special with 4 boys, very few people have that.