NEED ACADEMIC ADVICE SERIOUSLY!?

I am struggling badly with my academic. I finished my high school with average grades. I got into university in middle east, i started my chemical engineering there. i spent 1 and half year there, realized it wasnt the field tht was fit for me, so i transfered to USA for Industrial and Manufacturing engineering, i was there for about 6 months. The courses i got were interesting and i did good in few courses but sadly i did really bad in 2 courses. I realized that i was fit for engineering. I was into more of an architecture field. I was pretty much homesick in USA for odd reason. Then i came back to my own country and took admission in reputable architecture university. I started my study there in January 2009. I can say, i gave my best shot. i did watever i could do. but again today i recieved my result for 1 semister and i got 1.78 gpa. while i was in middle east i got 1.7, when i was at states i got 1.8. I dont know wat to do. please someone advice me. really struggling and worried abt my future.