feeding question....?

I am nursing my 2 month old son. My husband and i want to take our daughter to disney on ice tomorrow for her 5th birthday. I have enough milk pumped to leave for my son, but I will be gone for about six hours and will miss at least one, maybe 2 feedings. I had a really hard time getting my milk supply established in the beginning, if I miss those feedings will that affect my supply?