If you got to 2-3 months, then you made enough milk (by then BF babies have pretty much reached their maximum milk-munching-capacity). So from a supply point of view you should be OK.
The attachment is a bit of a worry - just because if you are doing twice as many feeds then there is twice the potential for damage.
You may find that you need to pump sometimes to give your nipples a break - do you have, or can you hire, a double pump and the correct size flanges for your nipples (I'm guessing that they may be larger than average, because that can make attaching harder)?

Remember the ABA telephone line - 1800 mum2mum - which can help you through some of the early "fun" too.