Stress is the result of life changes. You cannot prevent change from happening, just like you can't prevent stress from occurring. You can, however, control how you respond to stress.
Time management is a skill that one learns and practices. It is within your control to attain, and your projects and life goals are worth attaining it.
University life is a complicated animal for everyone. And relationships (romantic, friendship, or professional) are all part of being a college student!