I'm really sorry to hear about the struggles you're facing since your diagnosis. It's completely normal to feel overwhelmed and experience disruptions in sleep patterns during such a challenging time. Have you considered reaching out to a therapist or counselor who specializes in supporting cancer patients? They can provide coping strategies and support as per  your needs. Additionally, engaging in relaxation techniques like deep breathing, gentle exercise, or listening to calming music before bed might help improve sleep quality. One of my relative was dealing with sleeping issues, nightmares and palpitations due to serious health condition. She tried simple 30 min. of meditation before sleep and listened soothing musics. That helps her a lot. So you can try if it works for you too. Hope you get well soon. 

Thank you, I can access counselling through work so may resort to it if it doesn't improve. I thought it was down to the waiting before surgery and after that I'd be ok, but there's more waiting.