Hi -
I will be out of town for six days for work

Unfortunately, I am not going to be able to build a sufficient supply of EBM for the entire six days. As a result, I am going to have to supplement with formula. My daughter will be 14-weeks old at that time.
How do I start to supplement? Should my dh use at least a little breastmilk when he makes the formula? Which formula is best? I am just so sad about this, and so confused!
Any advice would be greatly appreciated!