5th Year of Undergrad or Masters?

I am currently finishing up my 3rd year of undergrad in biomedical science with a certificate in IT, and this last year has been a nightmare. I have a GPA of only 3.35, and am looking at a very heavy loaded 4th year (10 3rd/4th year biochem and biomed courses - so it will be tough). I am starting to consider taking a 5th year and spreading out those 10 courses over the 4 semesters and getting a certificate in science communication and taking some kinesiology classes to help up my GPA those two years. I also thought of doing a 1 year masters and just cramming in those hard classes and doing my best but I fear my GPA will drop or stay the same meaning I am not competitive enough for med. What should I do?