Starting alevels

I'm happy that you're all feeling excited to head straight into your next step to academical life, but I can't help but feel confused. I usually do quite well in academia, scoring high scores in sciences( particularly biology and chemistry), English lit and lang and the humanities( R.E and History). from yr 9, I thought I had discovered what I wanted to do and would dedicate every bit of energy I had to become it, fuelled on nothing but passion, but lately, I've stepped back a bit from that. I still want to go to med school, but I also want to be an author, and I can't shake that passion for history I still have. At the moment my A-levels are:
-Biology
-Chemistry
-History
-and EPQ
.I've always wanted to write since I was in yr5, reading anything I could get my hands on. for the past year, I've been coming up with plans and at the moment I feel like I just need a little bit of assistance(or motivation of some sort) as my mind has been going a little blank which is frustrating. For some reason, I thought that English lit could help sharpen my skills and teach me more techniques which could boost my writing skills.
.As for medicine, I've wanted to be a surgeon since yr 8, just to help others. money from the job was never a priority to me, I just wanted to help the world as much as I could I guess. I guess death changes your entire perspective, to a point where you'd do anything for others to not feel the same way you did, to just do your best to save lives rather than watch them...
.but history will always be a major part of me. surprisingly, it's gotten me out of really dark spots. let's just say that when I was feeling really low, I would open up a history book or research things from university grade history, mainly ancient history. that feeling of discovering something new or getting one step closer to fully understanding an entire picture is just great. for the past yr and a half, I've been considering to take history at uni instead. but would that make me selfish? I enjoy helping others though, but I also enjoy history and writing. do I just take an extra A-level? would that be significantly harder and really stress me out? what do I do if I was eligible to do either history or medicine at the end of A-levels after taking four A-levels? I don't know, I'm just a Lil confused. A little advice will mean a lot to me thanks.

ps: sorry for sounding like a self-absorbed prick, I'm just kinda stuck as you may have noticed, again, I am happy to see that everyone is happy and excited to move into the next stage of their lives, I just don't wanna be making a bad choice is all