Sure, we're here to help if we can, and I notice that we have.
I'll be blunt. The problem is not with your allin which is correct, but that you've made it too late. The other guy no matter what his stack or cards is probably right on betting at that flop without a raise from you preflop, and also when you put your chips in. say 2 xBB pre, his 600, your 1200 pot = 3000 . Even if you have the overpair to his eights he's getting 5 to 1 from the pot on 4 to 1 behind and its that way till the end. You let him into the pot with dross and gave him a price with his hand.
If you're in doubt as to the value of certain hands, talk with your fellow team member Jacks_off4me (egs500 at Carbon). He could tell you how to play K3os, Q6os, T5s, oh and A9os
Its also quite hard to sift the information from the OP and some is missing. Do you know how to post a hand history? I'd find it easier to reply if you could.