journalling is good, sometimes some exercise even walking can help. From what you have said about the flashbacks, not wanting to go to sleep at night (hypervilgience), not being able to keep your mind off those triggering thoughts, or feeling frozen (numbing of the senses) makes me think you are suffering from PTSD.
If that is the case, you just can't will things to go away. In fact the more energy you put in NOT thinking about stuff, will actually cause you to think MORE about it.

My T says that things happen when you have kids that can be BIG triggers to things in the past, she has seen this in a lot of SA and physical and emotional abuse survivors. I forgot how old your son it, but can you just tell him one on one that you aren't feeling well right now, that you still love him and that you are trying to get better? Kids usually know something is wrong anyway, but if you tell them the truth that you aren't doing well, it helps take away some of their anxiety.

I am not sure bringing your child into therapy was good timing for this by your T. Farmergirl, I care about you and am thinking about you.