I constantly clench my teeth without realising most of the time i think this habit is caused by emotions as i'm a hypochondriac how can i stop this before i get a tmj disorder or damage my teeth?

You should speak to your dentist about fabricating a custom bruxism guard. This will help prevent wear and tear on your teeth and TMJ, but will not stop you from clenching or grinding. Ask your physician for a referral to a therapist. You need to talk out your anxieties and receive counseling on how to deal with your issues.

You have already taken the first step. You realize that you have a mental health problem that is affecting your physical health. It's time to seek help from a mental health practitioner to help you address your hypochondria. It would also be prudent to see your Dentist for fabrication of an "Occlusal Orthotic" to protect the integrity of your dentition.