Hi lovely, 

I'm so so sorry to hear about your moms diagnosis, and also to hear you lost your dad a few years ago too. 

I lost my dad 4 weeks ago yesterday, he died very unexpectedly of a cardiac arrest 9 weeks into his diagnosis (we were told he had a lot longer, he deteriorated quite quickly but didn't suffer as he was still going to attend treatment). I'm still trying to process everything that's going on, especially now we have had his funeral. So I do genuinely know how you feel with some part of your grief, but the worry of your mom is something I can't even begin to fathom and I'm so so so sorry. 

I think one of the best things you can do is talk to your mom about your feelings, you'll probably find you'll be able to have more of that same relationship you had before once you get these feelings out. Anticipatory grief is a very real grief, when my dad was diagnosed I spent the first 2 weeks mourning him, and he was still here at home happy and on the surface very healthy. My dad refused to believe he was terminal but I knew from what they told us (potentially manageable but not curable) that he wasn't going to be here till the end of the year and he wasn't one thing that did help was talking to my dad, and other loved ones especially those who may know exactly how you feel, maybe siblings or close relatives. There's no quick fix, and no amount of conversations will take away the pain but it may relieve some anxieties. I know it's easier said than done, but I wish I had listened to those who said it, but take each day at a time and make the most of the days where mom feels up to going out and doing something. 
 

Losing a parent is devastating to say the least, but the worry of losing your surviving parent is indescribable and I'm so sorry. Please feel free to message me whenever if you need to talk 

Take care if you and your mom sweet xxx