Feeling sorry for myself

My daughter, my granddaughter, my great grandson and my husband all went down to play in the river and I am feeling very sad.  
I wish so much that I could go but I know that is not a good idea!  Both my daughter and my husband get very angry with me because I won't even try.  But it is in the high 90's and I know how hard it is for me to breath when it so dang hot outside.  
They think I just make excuses but I know what I can do and what I can't do.  I wish so much that they would understand.  But I guess that is wishing for too much.
I went out to dinner with my husband 2 nights in a row thinking I was accomplishing a lot, but it is never enough for him.  I can't keep up with him and it really makes me sad, but I have to face the reality even if he can't or won't.  There are certain instances where I simply cannot breathe and I try not to put myself in those situations.  
So here I am writing in a journal that not many people will read and feeling very alone.