Serious reasons, including illness and necessary care of infants, can excuse a Catholic from the Sunday obligation. Deliberately choosing to miss without a serious reason is a different situation.
A little more context
If you cannot attend, pray as you are able. A livestream may help you pray, but it is not sacramental attendance at Mass. You do not need to endanger yourself or neglect someone’s essential care. A priest can help you discern a complicated or recurring situation.
A practical beginning
When you are sick, keep the day gently: a brief prayer, a Gospel reading or a quiet act of gratitude may be enough. Contact your parish if you need pastoral care or Communion brought to a homebound person.
Source & further reading
Catechism 2180–2183: obligation and serious reasons (opens in a new tab)↗Teaching summaries are introductions. Follow the linked Church source for its fuller context.