Have you had any symptoms? What do you mean by 'off'? The best thing you can do is take a test. Also if the condom ripped he should have told you. It's your body and if something like that happened and he didn't tell you in the moment it suggests he's not trust worthy to me.
You don't have to buy an expensive test, a dollar/pound store test will do just fine, they are just as effective get two just in case. (They use the same ones in hospitals and clinics).
Honestly though if you think you may be pregnant just take a test or go see your GP. There's not much we can do here but speculate.
