What will happen if I don't breastfeed one day?

I have to go to a whole bunch of appts next week one day and I'm worried about my supply going away if I don't breastfeed or pump for a full day. Not because I don't want to I just have to get these appts taken care of.

I've only been breastfeeding for about 3 weeks and trying to increase my supply so that's why I'm anxious about it. Any input would be helpful, thanks so much.