I'm only in year 12 so I can't provide a lot of insight, but I can try advise you a little.
• If you hate physics, are you sure you'll enjoy astrophysics/astronomy? Both of those are very much like the rest of physics, full of a lot of maths and such.
• It is possible to get into a medicine course without biology but it's difficult. Not having biology will put you at a serious disadvantage.
• My advice would be to try and decide what you want to study after A levels. If it's any kind of engineering, don't drop physics. If it's medicine, drop physics or economics for biology. If it's finance, then your current subjects are fine.
Just keep in mind that I don't really know what I'm talking about. I'm just hoping that I helped clear up some of your thoughts.