I am an apprentice and I’m bad with money. I need help with learning how to handle money.

Hi, I (24F) live with my Fiancé (30M). We both are in an apprenticeship and live in Germany. We don’t earn much (400€+470€) and live in a social flat (370€ rent). We pay electricity and water monthly. He pays the rent and utilities and I pay for everything else. I rarely buy/eat meat and the environment is really important to me. I try to incorporate that as much in my shopping as I can but it shows financially. I’m also fighting depression (I have medical care/a therapist) and I tend to be impulsive with buying stuff when I’m feeling horrible (cake, clothes, sweets etc.) Even though I don’t need it/ it does make me feel more guilty. I never really learned how to handle money in the first place and I’m really struggling to control my impulses. I do the grocery shopping because I also cook and I commute to my school while my boyfriend works Homeoffice. Where can I start? Does someone have similar problems? I really need help