Cannot find 11 gig storage after flashing to a custom rom

Good day... I just have my galaxy s2 flash with a custom rom and before that I have a stock rom installed and it has a 11 gig internal storage but now after flashing it only shows 2 gig of internal storage... Also when I plug it in on my computer the 11 gig storage doesn't show up unlike before when I have the stock rom... Can anyone help me fix my problem... By the way the custom rom I installed is Cynanogen 12.1