One of the reasons lo's cluster feed in the evening is the naturally lower supply. Prolactin peaks between 4-7 am, and is lowest between 4-7pm (ish). As Tay says, demand feeding is best for supply and best for baby - it sorts itself out.
Also make sure you are taking a break and getting fed/hydrated in the afternoon - often it is a busy/stressful time, and it is good for mom and her milk to slow down and put your feet up! One day off schedule should not affect your supply unless compounded by a change in diet/medication/illness, etc.
Also be aware of hormonal changes - even if you don't have your period back yet, your hormones may fluctuate during the month. if you do have your period back, then the week before and/or during can be a time of lower supply. Taking calcium+magnesium during that time period helps a lot.