Sometimes researchers, particularly those who are new in a lab, try to set deadlines for all research goals. Although progress is important, and so is setting goals each semester, not every goal needs a deadline.
It is only through the conscious practice of time-management, and prioritizing the activities that are important to you, that you will achieve a solid academic/life balance.
Take time at the end of each semester to ask yourself, "What worked for me, and what didn't?" Then, to help keep your priorities in check without becoming overextended, cut low-value activities, only continue with ones that make you happy, and make finding time for yourself a priority.
One of the biggest mistakes scientists at all levels make is planning to do too much in too little time. We all believe things will go faster, be easier, and take less time to accomplish than they actually do. Setting research goals is important, but so is adjusting them when needed. NEVER let yourself feel that you failed for reevaluating what is reasonable to accomplish. It's simply part of EVERYONE'S research experience.