When you are unable to leave home, you can still unite yourself to Jesus in a spiritual way.
For a number of reasons, we may be stuck at home and unable to attend Mass. One of the most difficult parts of this cross is the inability to receive holy communion.
When presented with such a situation, the Church recommends to us an ancient practice of “spiritual communion.” It essentially consists of relating to God your desire to receive him in holy communion, spiritually uniting yourself to him in an intimate and personal way.
St. John Paul II praised such a practice in his encyclical, Ecclesia de Eucharistia.
[I]t is good to cultivate in our hearts a constant desire for the sacrament of the Eucharist. This was the origin of the practice of “spiritual communion,” which has happily been established in the Church for centuries and recommended by saints who were masters of the spiritual life. Saint Teresa of Jesus wrote: “When you do not receive communion and you do not attend Mass, you can make a spiritual communion, which is a most beneficial practice; by it the love of God will be greatly impressed on you.”
It is believed that those who make a spiritual communion can receive many spiritual graces from God, strengthening them in their trial.
Here is an example of such a prayer from the Golden Manual, that can be used to express your sincere desire to unite yourself to Jesus in a spiritual communion.
O my God, ocean of holy love and sweetness, come and give yourself to my soul. Grant that with a perfect heart, full desire, and burning affection, I may unceasingly desire after you, and lovingly rest in you. May I prefer you to every creature, for you renounce every transitory delight, O my true, my highest joy!
Feed me, Lord, a poor, famished beggar, with continual draughts of your love; refresh me with the wished-for presence of your grace. This I seek, this I long for, that a vehement love may penetrate me through and through, and fill me.
Grant, O most loving Redeemer, that I may be wholly inflamed with the love of you, that I may delight only in you. O overflowing abyss of divinity! Draw me to you, and immerse me in yourself; so seize and take to yourself all the affection of my heart. Amen.