Why do I owe more this year?

I’m doing my taxes for the first time and I was proud of myself until I saw I owe almost $1k more than last year. The big difference is I started doing freelance work and started earning extra income, but according to TurboTax, my business income is only $370 and from what I read, I pay self-employment tax if I have an income greater than $400, so I don’t understand why I owe so much more. I have treasury bills and a high-yield savings account and I’ve generated about 10 K in interest, but I haven’t sold any of my stocks. Would the larger amount of interest that I accrued this year (compared to last year) be the reason why I owe $1k more?