rush

i went through rush this fall, and after the first round I ranked g phi as my number one, and the next round i wasn't invited back. usually this type of thing wouldnt bother me but when i talked to my friends about this, who are in g phi, they were all so confused when they didn't see my name on the list. i still go to all their parties as a 'date' and hang out with all the girls, but of course i actually want to be in it too. what are the reasons i didnt get asked back? was it because they were in such high demand? and if i rushed as a sophomore, would i have a good chance of joining the house since i know and hang out with everyone in it already?