It sounds to me that you're depressed, which would explain your ambivalence and indecision and loss of ambition. The first thing you should do is stop comparing yourself to your peers. It doesn't matter if you graduate later than they do - it's not a reflection of your self worth in any way.
Civil engineering is so different from retailing clothing on Instagram, I don't know what to say about that. Business and marketing are very different skills from those needed for civil engineering.
Here in the US, the Dept. of Labor publishes a career guide every 5 years. It lists every type of legal job in the country, the average salary, the educational requirements, and forecasts for growth over the next 5 years. The UK might publish something similar. Also, here we can take state sponsored vocational evaluation tests. These help narrow down skills. It's due to this type of test that I found out I have attention deficit disorder, a revelation that made a lot of sense to me. It's why I got so lost in factories and noisy work environments.
Very few of us wind up with a job that makes us happy. People who do manage that are extremely fortunate. Most of us do well if we can find something meaningful that pays well.