I am scrupulous, and I know I am probably being paranoid, but I wanted to affirm my answer or suspicions.
Is it a sin to think of what we want to be in the future and what we want to do, like:
go to college and even to go on web sites of colleges we want to go, or
to [plan/talk] about buying something in the future, like a new computer
on Holy days, like Sundays?
I know it's not good to shop on Holy days if it is not a necessity, so are these sins
or am I just being paranoid?
Is it a sin to do things on Sunday that lead toward a vocation or calling we have? }
Hi, Scrupulous —
Yeah, I think you are being a little too scrupulous.
There is nothing wrong with researching information related to a future vocational calling you have, either inside or outside of the Church. Buying something like a computer though, can probably wait until Monday.
Again, the focus of Sunday should be as a day of rest and relaxation.
2184 Just as God "rested on the seventh day from all his work which he had done," human life has a rhythm of work and rest. The institution of the Lord's Day helps everyone enjoy adequate rest and leisure to cultivate their familial, cultural, social, and religious lives.
2185 On Sundays and other holy days of obligation, the faithful are to refrain from engaging in work or activities that hinder the worship owed to God, the joy proper to the Lord's Day, the performance of the works of mercy, and the appropriate relaxation of mind and body. Family needs or important social service can legitimately excuse from the obligation of Sunday rest. The faithful should see to it that legitimate excuses do not lead to habits prejudicial to religion, family life, and health.
The charity of truth seeks holy leisure - the necessity of charity accepts just work.
— St. Augustine, De civ. Dei 19,19:PL 41,647.
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.
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.
2188 In respecting religious liberty and the common good of all, Christians should seek recognition of Sundays and the Church's holy days as legal holidays. They have to give everyone a public example of prayer, respect, and joy and defend their traditions as a precious contribution to the spiritual life of society. If a country's legislation or other reasons require work on Sunday, the day should nevertheless be lived as the day of our deliverance which lets us share in this "festal gathering," this "assembly of the firstborn who are enrolled in heaven."
I hope this helps,
Also see Blessed John Paul II's work on this topic: