Laura,
I am so sorry to hear about your dad. Eternal rest be granted unto him oh Lord, and may Your perpetual light shine upon him always.
Laura, I know what it is like to be a mom and feel you need to "keep it together" all the time. I also believe though, that you need to care for yourself so that your children get your best care, and you can't care for others unless you are whole. Your son most certainly senses your stress, even if he doesn't know about it.
This site is excellent. Find a friend, see a counselor, and don't be at all afraid to take care of yourself through this. I don't know if you are the praying type, but if you are that helps too. If you want to PM me just to cry, please do so...I am always here (my husband says I am addicted to this site!). That way you can unload on someone you don't even know!!
Bless you and keep you and take care of you!