Sad and tired niece. Any advice?

Hello. I have been lurking here for a long time and have found it helpful. It’s my turn. In Jan 2021 my Dad passed away. He was the main caretaker for my Aunt with early onset dementia. I suspect some mental disorder as well because she’s been a little off her whole life. She has never been married or had children.

She came to live with me when he passed and it’s been very hard. She never worked only lived off inheritance so she never paid into SSI or Medicare.

We see now “spending down” her inheritance and paying a Medicare Full premium of $800/month. Last was the worst night we have ever had as far as combativeness and almost injuring my pet. I’m a married working 34 y/o with a teenage daughter. It is time for placement but I feel like such a failure and so sad. My sister tries to be supportive but has her own life. I was the one with an extra bedroom. I find myself sad, depressed and my “fuse” is nonexistent. All of my relationships are suffering bc of my burn out. I know what I need to do but I’m so sad. The price or Memory care is about $7k a month. I have to hope we can manage 5 years for the Medicaid look back. She spends money on Medicare, medical bills, Walmart, DoorDash because she can’t drive and a small storage unit. It is so much pressure not to screw up her spend down. My day job is personal attendant to my step sister who is legally blind with intellectual disabilities so going to work and then coming home to more caregiving is nuts. I feel hopeless and like I serve no purpose other than this. I’m scared my Aunt will hate me and my Dad would be mad at me (he refused to place her). Thanks for just reading it you made it this far. Many of you have really helped me not even knowing it.