Being Asked to Delay Graduation for Dissertation

Hi everyone,
I’m a third-year International Relations student, and I’ve been advised by my course leaders to delay my graduation until next year. The reason is that I have some modules I need to retake, and they want me to spend a fourth year focused solely on completing my dissertation. I’m upset because I know I can complete the modules and I’ll be fine, I’m really determined to graduate on time, but I’m unsure how to proceed. Has anyone been in a similar situation where they had to retake modules and complete their dissertation without delaying graduation? How did you manage, and were there any ways to avoid the delay? I would really appreciate any advice or experiences you could share.
Thanks!