You are stuck on the idea that the only way to move forward is to go backward to some idealized version of what you interpreted as everybody else having the time of their lives. I am absolutely sure that if you could get those people that you watched playing in the pool outside your window and ask them now ‘wasn’t college the best time ever?!’ you would get a much bigger range of answers than you imagine. You don’t know the private side of their lives- just the public show.
Actually, no. The ‘self’ that matters is your future self.
You have a subject that you say you are passionate about- what are you actually doing about that? You can switch from one subject to another between undergrad and grad (says somebody who did it) - and you do it by getting some experience in the field. So, you go take some classes in film at your local community college and while you are doing that you research masters programs, and apply to them. Bonus: a masters will cost a lot less money than another 4 years of undergrad, and grad school is more fun than undergrad (says somebody who went back twice, first for a masters and later for a PhD. Exams still suck but the classes are more fun and they mostly treat you as a peer).
Nobody here is saying to throw in the towel. But pretty much every poster has said some variant of ‘the past is a foreign country’ and you can’t go there / change it now. Look forward. Parents watch their kids take all kinds of detours as they find their path in life. I am pretty sure that yours would rather that you take concrete steps to go forward than to say ‘do-over!’ and go backwards.