Crying inside

My middle son who is the only one who seems to care about me announced they will not be coming over as much if their dog can't come inside as winter is coming.   He says they can't leave the dog inside all day.
They do all the time.  They got to work at 8am and get home and let the dog out at 4pm.  They come over at like 1pm-2pm on Sundays and leave at 8 or 9pm.  It is the same amount of time.
I have a cat.  She doesn't like their dog.  He plays in the yard, but not in the house as she hisses at him.   He already cut out his visits on Thursdays.  He used to come by every Thursday and now says he is too busy.  He said he isn't going to most of the Saturday events we go too.   Told me that two weeks ago.  Guess Sundays are leaving too.
He was all I had left and now he doesn't want to spend time with me any more either.   And I can't say anything as he says I use guilt to get my way all the time.
My heart hurts, can't breathe....just want to go somewhere and be alone.  But then I already am...