Quitting an A-Level

I decided to quit my Ancient History A-Level because I have been struggling with it for the entire year and a half I’ve been studying it and it is bringing down my mental health (and possibly subsequently my physical health). I know nothing about the course and if I were to want to pass I’d have to essentially teach myself the entire course in a couple of months - I am passionate about my other two subjects and would rather spend the time working on getting better grades for them. I feel apathetic towards History at best and don’t think it’s worth the effort. However, I am still overwhelmed with guilt about my choice; I feel that I am lazy and just taking the easy way out rather than doing what would be morally right and working my socks off to get better. I don’t think that only having two A-Levels will impact my uni offers or life in any way, but I still feel a sense of obligation towards the subject even though I am mostly happy with the decision to quit it aside from this guilt. Am I a lazy person for doing this?