iso help for my cat

hi everyone. I've been scouring the internet today for resources to help, and ive come to reddit. I'm 19 years old and in foster care, living in a state program run apartment with my cat smokey. she's my soul cat and I love her so much, and i think theres something wrong. shes been acting weird, and I know she needs to go to the vet immediately. I have a job and a car, but I'm living completely paycheck to paycheck. I have to ration food every day to make ends meet, and the required multiple weekly meetings with case workers make it so I cant go full time. I'm surviving off of doordash between payday, and I need some help to get smokey to the vet.
I'm asking really anything, no more than $300 dollars.
I have cashapp and venmo, even just a little gas money so I can doordash more would make my life easier. thank you in advance!!