Wanna get over wid guilt....?

i m a bright student but last year due to some reasons my mind was kinda diverted away from my goal.....well this goal was one of my parents dream...and my dream too....it was regarding gettin admission in one of the best universities in my country...one year has passed away...i hv realised my mistake....i know i was capable of doin it....but i didnt try my best.....the guilt is haunting me now....well i m presently studin in a good institution but my dream...most importantly my parents dream has been shattered.....I WANNA GET OVER WID THE GUILT.....tried to convince myself...everytime when i take a look at the students from my 'dream university' i cant just take it...its killing me...what can i do??? plz help me out.....feeling very low and hate myself for my mistakes.....