Self study AS Level physics, is it possible?

I only have a few to go until my exams start, and I'm definitely going to fail history... I know I should've done something about that a looong time ago, but I thought I could do it until now :/ (that's really stupid of me i know i know...)
I know it's impossible to do the exams this June, but IAL Edexcel introduced October exams this year, so I might do that then (and if not i can just do the exams on January next year), and start studying the subject from now. I already self studied gcse psychology last year in one year and I got a good mark, so I know I can definitely study a subject on my own, and I did really well in igcse physics and I like the subject. However, I know I can't compare an easy-ish gcse subject with A level physics. I heard it's really tough and most of my friends got low marks in their January exam, so I'm really really worried. The problem is I don't really have a choice. It's either I definitely fail history... or maybe pass maybe fail physics???
Anyone self studied physics or a similarly difficult subject before?