Hi there
OCD is an anxiety spectrum disorder and in any such disorder biological functions and normal physiology of our body can get affected. So in a person suffering from OCD, loss of appetite and indigestion can very well be seen. Taking a medicine to correct it (for example: Rabeprazole) can correct these symptoms superficially. But to correct the root behind these symptoms, we need to take care of the the cause.
For OCD, medication is not the only way out. Psychological intervention with or without medicines can be really helpful.
Next Steps
Consult your mental health professional.
Health Tips
Even if you want to do certain things at home, do meet a professional, discuss the case at length and take a professional help.