A complicated question???

hi,i suppose i am really good at math.however i am doing BS mathematics(freshman) at a university here in bangladesh. the fact is my faculty isnt really good...sometimes i feel like i am just in the wrong place. but i want it somuch to major in mathematics and later go on to some american graduate school in the NUCLEAR ENGINEERING field...sometimes i lose all my motivation, i had tried for moving to canada as an undergraduate for a better education but i had been refused for the visa as i couldnt show sufficient money at that time.sometimes i feel i wanna cry alone but cant do that either(dunno why).its so complicated...but all i wanna do right now is to do very well with my grades and complete the BS here at this university and then later go for a good graduate school somewhere in the usa or canada...i'v a tendency to learn my lessons all by myself at home even when i could share it with my teachers or friends.im bit shy.i soon wanna take GRE (within 1 and half year).any help,advice??