Need a way to leave the bitterness behind

I don't know if anyone has had this problem, but I realize that I have become intensely bitter. I mean to bring this up with the counselor I'm seeing, but if anybody has experience with this I would like your thoughts. I was in the hospital thanksgiving week for my pe, after having a hysterectomy a couple weeks before. I felt unwell already. I was so scared  of dying or being alone that I actually was glad to be in the hospital on thanksgiving.  My husband had to work, and at least some of the nurses and aides were cool. 
I've never been a big holiday person. I dislike the pressure and commercialism that are usually part of the package. But now, I'm traumatized by them. I do not have a good relationship with my mom, and my sister and I are not close. I spent an hour at my sister's gathering on Christmas eve, and it was just so emotionally painful. I should have been happy to be an aunt to her new baby. I should have been making wisecracks like I used to. Instead, I had to force myself from bawling. So many people there...so much life going on...seeing a vivid picture of how life goes on for people I know made me suddenly feel so frail and meaningless. I saw how easy it would be for me to just be an empty chair and vague memory. I couldn't choke out a merry Christmas, it would've felt so hollow.
As I tried to get back to working and venturing out, I was stricken with how intensely bitter I felt when people fretted about things like presents, traffic, lattes, their shoes, etc...  It was as if I didn't belong in their world anymore. I longed to have the sort of innocence/ignorance to be so concerned with the small everyday things. I just can't relate, and it makes me feel even more alone. By the same token, nobody can relate to me. 
I don't know how to move past it.