A-Levels

So basically, I'm supposed to make my choices for a level subjects tomorrow and I thought I knew what I wanted to do but now I'm not really sure and I'm kinda having a slight crisis over this and I'm on the verge of some kind of panic attack and I really can't deal with school being this stressful again before it's even started. Does anyone have any advice?

What did you originally want to do?
what do you want to do now?
what made you change your mind