why did i fail the 1hr glucose test? help!

S • ‘16 MC, ‘17 boy, ‘20 boy
I took the 1hr test this morn, they said anything above 120mg in your blood was abnormal and i was at 143. Ive seen other drs make the cutoff 140 or 130? Why was mine 120?
I have to fast 12 hours and do the 3 hour test tomorrow. What can i do to pass???