Everything went wrong, now wat? wat can i do?

my girlfriend and i were standing on her front porch after a date and were just whispering to eah other and saying good nite, after a while she just breaks off the talking and looks into my eyes then she blurts out i love you, shes never said that to me before and shes told me she never said it to any guy before so yeah its must have been special for her, i just like froze and was silent for about 2-3 minutes, after a bit i say"um..yeah, so good nite, ill call you" she looked dismayed, she pushed me away and stood there. after a long silent arkward moment she says, you can leave now, go away.i try talk to her but its no use so i leave and i here her slam the door behind me. afterwards were back to being like normal 4 about a month.but 2 days after summer started she went to europe, without telling me. just out of the blue. now i need deep thoughtful answers and if you can yze it somemore great, and dont say im stupid i know that part,