I struggle to save and not make large "necessity" purchases after so long going without--Can't shake poverty mindset. How do I overcome this?

For context i come from a single mom/paycheck-to-paycheck family, I'm on disability, and newly work very part time as a nanny. I am almost entirely debt free and track my spending well, but have trouble sticking to a budget because of my poverty mindset. My health has been bad for years and I've been close to homelessness so many times. So it's safe to say the worry about going back to that is always at the forefront of my mind.

Because of the nanny job I have some financial flexibility for the first time in years now. Being able to pay my rent and have extra to save or use at my discretion is amazing. A miracle. My job and health are both pretty shaky, however, and so everything I earn seems to disappear to something I've needed for years and couldn't buy. Last month it was emergency weather supplies (propane heater, food, etc.) because I live alone, don't have family here etc. Last night I bought a laptop, because I've been using the same one for 13 years and it barely works now, I bought this new one--the cheapest I could find, a $200 Lenovo--because if I'm let go I'll need it to work with, etc. Later this month I'm paying for medical treatments I've needed, but could never afford before, etc.

My problem is I've gone without for so long, and I'm always one step away from going back to that. So my mindset is: "I'm going to need this when I'm out of work." But I really want to be able to save up for 6 months emergency fund, like if i stop receiving disability suddenly or lose my job. But there's always something else I need, it seems.

I asked a friend who is very good with her family's budget for advice, but she was unhelpful because she's never actually experienced poverty. She said "you just tell yourself you'll have the money later" LOL, sure. I'm sure that's true for some people, but poverty is just a reality for others. I'm a single woman with no family aid and debilitating health issues, the money will not reliably be there later. The Dave Ramsey mindset doesn't work for people like me. So i would LOVE to hear your stories and experiences and what worked for you if you can relate at all to this mindset.

Side note if anyone has any ideas on remote part time work I'm all ears!

Edit: grammatical errors