I am taking general chem I + lab, Microbio + lab, history, trigonometry and spanish, and I'm struggling?

I am having a hard time finding a balance to study everything. Last semester I only took one science class, a math class, 2 other electives classes and did much better. My science classes are taking so much of my time and I hardly have time to focus on the other classes it's affecting my grades. this week alone I only slept for only 5 hours and it's affecting me during the day time. I feel tired and sleepy. I am thinking about dropping one science class and take it again this summer. Is that a good idea?