As TT, we were going heavy MM and rush at the 6-minute mark. However, since the map is too large, by the time we got there, they have already expanded and have enough zerlings + banelings.
What else could I have done?
Rushes are usually most effective on small maps. On a large map your opponent has more time to prepare because it takes so long for your army to reach his base.
So on large maps it is often better to not go for a rush. Terran is good at defending, so you could have walled yourself in and defended, while getting your economy going and building up for a later but stronger push.
On big maps I would suggest to make small pressure on opponent, to have understanding what they are doing... and expand yourself too. After that - personally I would recommend to go tech.
Once again, as sth told too: big maps are not good for early rush.
What else you could do? You MUST know that they have bannelings BEFORE you push: SCAN them or use 1 helions to see what is going on there... Once more information about their action is received try to counter that.