but now realize what I was doing seems wrong.
In light of what the Catechism says
I don’t think you are doing something wrong, but those who are coming to your restaurant who are Catholic or Christian, just because they are lazy and don’t want to make breakfast at home might be doing something wrong. Visitors coming from out of town who are staying at hotels or have some other mitigating circumstance are probably not doing something wrong by eating at a restaurant on Sunday, especially if they do not have another way of getting food. See the Catechism quotes below in bold.
I always do my shopping on other days of the week so I am prepared for Sunday. I almost never will go out to a restaurant on an Sunday. If I do, it is because someone might be visiting and I don’t want to prepare a meal, or because I have pressure from family or friends to do so.
**CCC 2186 Those Christians who have leisure should be mindful of their brethren who have the same needs and the same rights, yet cannot rest from work because of poverty and misery. Sunday is traditionally consecrated by Christian piety to good works and humble service of the sick, the infirm, and the elderly. Christians will also sanctify Sunday by devoting time and care to their families and relatives, often difficult to do on other days of the week. Sunday is a time for reflection, silence, cultivation of the mind, and meditation which furthers the growth of the Christian interior life.
CCC 2187 Sanctifying Sundays and holy days requires a common effort. Every Christian should avoid making unnecessary demands on others that would hinder them from observing the Lord’s Day. Traditional activities (sport, restaurants, etc.), and social necessities (public services, etc.), require some people to work on Sundays, but everyone should still take care to set aside sufficient time for leisure. With temperance and charity the faithful will see to it that they avoid the excesses and violence sometimes associated with popular leisure activities. In spite of economic constraints, public authorities should ensure citizens a time intended for rest and divine worship. Employers have a similar obligation toward their employees.**