Declaring Major in BMSC - Please Help!

I'm in my second year of BMSc, so I know that I am meant to be declaring my major at the end of this semester. I am currently enrolled in a full course load, including BMSC 230, and I am already really struggling to balance everything. I'm considering dropping 230 and taking it over the spring and summer, but I just checked the requirements for declaring your major in BMSC, and you have to have all your M4 classes finished before you are allowed to declare at the end of this semester. If I drop 230, I wont meet this requirement, even though I intend to take it in the spring and summer

Will I seriously have to wait a whole extra year to be able to declare my major? Will that have any negative impact on me and the courses I can take next year? I seriously do not think I can handle taking the course this semester without potentially failing and harming my grades in my other classes, but I do not know what this will mean for me in terms of declaring my major and what classes I will take next year. I can't get in to speak with a BMSC advisor right now, but I would like to drop any classes I have to as soon as possible so as to not waste more money than I need to.

Thanks