This concept has certainly been around a long time. My sister’s coursework was kept as they wanted to use it in exhibitions to promote the school to future students (which I think is the main purpose). That was back in the 70s.
If you signed an application form it almost certainly included terms and conditions. Some of those could easily have been an assignment of rights. As always the best thing to do is to go talk to your tutor and start to find out if it wil be possible to get these rights back in the future. If not then you just learned a valuable lesson regarding IP rights.