So anxious about my mum dying

So my mum isn’t doing too good at the moment. She’s got some chronic pain so she can’t leave the house that much. I’m just so scared of waking up one day or coming home from work and finding her dead. Just now (it’s midnight at the time of making this post) I got out of bed to use the bathroom and when I went past her room I always listen out to see if she’s snoring so like I know she’s alive, and this time I didn’t hear her snoring. So I asked her if she was awake and she didn’t answer. I’ve been dealing with my anxiety pretty well recently but then I felt all the symptoms of my anxiety coming back. I eventually went back into her room with my phone light and acted like I was looking for something. When I heard her asking me if I was okay I said yeah sorry just looking for something. But when I went back into my room I literally started sobbing from relief. I’m so close to my mum, we’ve never really argued. She’s the only person on earth I feel like I have a bond with and I don’t think I could manage her not being here