more and more I am regreting my life choice of going into art, and finding myself more interested in astronomy and physics and such. On an average week morning, my housemate will be downstairs watching the culture show or something, and I'll be in my room watching something on quantum theory or the big bang
Undergraduate physics is 90% boring stuff like classical mechanics (Newton's laws and onwards), thermodynamics etc., and then heaps and heaps of math. Sometimes when you get to the cool stuff you don't even realize it, it's probably just another a big pile of matrices with this property and that theorem and if you multiply it with this you get this and that and whooooops, somewhere there between the million sigmas was a result that makes a cool headline for a popular science magazine.
Not saying it isn't awesome when you get it, and good lecturers motivate with sidenotes like that, but mostly it's just more math. The one exception in my undergrad physics has been introduction to special relativity, which was filled with mind bending examples of how to drive a 6m car to 4m garage. Special relativity is a great in the sense that it's probably the only part of modern (relativity+quantum) physics that doesn't require much more than highschool level math as a basis. Often the best part comes sometime after you've done a course and you browse through the material and can skip all the mathematical technicalities and focus on the big picture.
I get what you mean though, I'm often thinking why didn't I go to philosophy or psychology or something, I would only have to read books and talk cool, grass is always greener on the other side. But when somebody's talking about the revolutionary new ways Kant had for thinking about perception he never mentions that in the original texts they are buried in a thousand pages of incomprehensible rambling. Which is natural of course, not criticising it, but you sometimes need a reminder.
If you wanna do the open university thing you can find lots of course materials online for free, MIT has its OpenCourseWare and googling around I've often ran into lecture notes or even video lectures from Caltech, Berkeley, Stanford etc.