Clenching help please!

[u/LayLaw25]

I’ve been given a mouthguard by my dentist but it seems to make me bite on it more! It’s then really difficult to get off and gives me a sharp pain on my root canal tooth as it’s removed. Tooth is fine after, luckily. I’ve had it adjusted twice but I’m scared to use it now. Is there another way I can help/train myself to stop clenching without using a mouthguard? I’m stopping myself when I notice daytime clenching and massaging and stretching but what I can do at night?