Not being able to stop thinking is exhausting. It probably is mental in origin, but have you ruled out physical causes of tiredness first? Some meds can cause severe grogginess - are you on antidepressants or any other meds?
On the other hand, if you've not tried an antidepressant that's probably the next logical step. Along with therapy to address (hopefully) the root causes of the thoughts and the being unable to forget.
Dx Crohn's in June 2000. (Yay )
Tried: 5-ASAs, azathioprine, 6MP, Remicade, methotrexate, Humira, diets.
1st surgery 20/2/13 - subtotal colectomy with end ileostomy.
2nd surgery 10/7/15 - ileorectal anastomosis. Stoma reversed and ileum connected to the rectum.
Current status: Chronic flare. Do I have any other kind?
Current meds: 50mg 6MP; Entyvio (started 3/11/16)