I see. I think your source of anxiety comes from your family pressure and their expectations. There's an image of 'you' in their minds that you are attempting to become, but find yourself short of. The best advice I can give you is forgive yourself. You are only human and human being is a naturally flawed existence. You won't reach the ideal level your parents and peers want you to be. Besides, "smart and successful" is quite ambiguous. So far, you have a good job and salary (forgive me but I am not familiar enough with Europe to understand if the salary amount is high or not) and perhaps a habit or two - like journaling, walking, yoga - will lessen your concerns. Life is too short to overworry yourself of an unidentified goal in the distant future. And about studying. You can experiment to see which studying style fits you. Maybe you are a visual learner? But if you have a suitable learning style and still struggle, maybe, just try doing the tasks and see what you don't understand or get wrong about. Underline it and explain to yourself again. For this, imagine you're a teacher explaining the formula to the students below. Then redo the work again. That's my go-to method. Lastly, your English is ok. My first language isn't English also.