I can't relate to such a situation but my mum was very poorly a few years ago for an elongated time and I know that anxiety and upset, however not to the extent that you must be managing with. 
 

 Try to think about how she would want to see you when she spends time with you, although there will be an internal battle going on for both of you separately, it's making those memories as valuable and special as you can and enjoying every minute you have together. Try to sleep even if you feel like you can't because it helps your mental state and is a little relief, even if In the morning it all feels heavy again. You're not alone and you are doing amazingly well, even if everything feels terrible, you're brave. Xx