how would you rate the difficulty of the "CCIE RSv5 Workbook Troubleshooting Labs" compared to the real exam?
Don't worry about the exams. You are not the only one who went through this and everyone had problems with their studies. All this is solved easily. Your health is more important. Also, you can at any time find help with lab report writing on the original source and professionals will help you. So do not worry, you will pass the exam and graduate well from college.
INE TS labs and Configs labs on main wb are a bit harder then real thing; Some tasks of INE go deeply into particular technology. Both have some ticket hard and some easy ones but just level or deep of knowledge for some of those is high on INE.