Do you know what's making you feel defeated and tired?
If it's the volume of information, you may want to review your study skills and see if you can find some new ones.
If the information is boring, maybe you're not cut out for med-surg. Learn it well - it's an excellent and irreplaceable basis for all kinds of nursing - and remember you're not stuck there.
If you're physically tired, well - nursing school
is exhausting. Don't neglect your self care - eat properly, including treats; sleep enough, play enough, get physical exercise.
Does your school facilitate small groups for clinical work? Can you debrief with your colleagues?