I think what is becoming clear now is that a significant number of our leaders are at least confused in their ecclesiology, and some of the hierarchy clearly desire to change essential Catholic doctrines. The schism is manifesting itself.
What to do? The internet is thick with calls to action, among which are some alleged private revelations. These well-meaning people call us to pray and fast, which is essential to Catholicism but little practiced. The alleged visionaries also urge particular practices, such as putting an ichthys symbol on our doorposts or wearing a rosary around our neck.
There is nothing wrong with painting Christian symbols on our doorposts, but please don't think that unless we do extraordinary practices God will not protect us. Our Lady of Fatima (God's revelation for the modern age) provides us all the direction we need for these times. Nothing is happening that God’s mother did not prophecy, nor is anything happening without her motherly protection. It is only up to us to do what God asks of us through his Holy Mother.
I wouldn’t jump into special practices such as the ichthys symbol. I urge you, rather, to study the history and messages from Fatima. I recommend Fr. Andrew Apostoli's Fatima for Today as a starting point. His suggestions for further reading at the end of the book will direct you from there. But even before studying these approved messages, you can do what she asked right now, if you are not already doing so: daily rosary, fasting once a week, and keeping the First Saturdays. We only have to be men and women of prayer, and God will do the rest. This is a frightening time for faithful Catholics, but also a time of great clarity. Evil is being exposed by the brilliant light of God’s grace. God is cleansing His Church, so let’s join Our Lady and be an essential part of this purification.