extreme fatigue SOS I need helo I have exams

Margo

I'm during my exams period and my relationship isn't at its best

I've been feeling extremely low levels of energy lately which are keeping me for even trying to work on either of those

my diet hasn't changed much

and drinking more water barely made any difference

as far as my cycle goes I'm in my last day of my fertile window but I haven't had sex since before my last period

what do you think could be causing it and how can I fix it?