Does anyone have any tips for obsessing about weight gain? Or compulsions involving counting calories? I tend to only feel ok if I'm eating foods that I deem to be healthy and if I want "junk" food it almost feels catastrophic.

I went through a period of this and ended up underweight because of it- I didn't want to lose weight it was just the illusion of control that counting calories gave me, exactly like my contamination compulsions now. I'd recommend bringing it up to your therapist asap and be careful it doesn't develop into an eating disorder. Good luck!