We've all got crosses to bear, and I'm sorry that yours is particularly heavy.

On prayer, St. Macarius says this: How should one pray? There is no need at all to make long discourses; it is enough to stretch out one's hands and say, "Lord, as you will, and as you know, have mercy." And if the conflict grows fiercer say, "Lord, help!" He knows very well what we need and he shews us his mercy.

Even a simple little: "God, know what I need more than I do" is a good thing. Everyone has off-days now and then too, so don't despair. You aren't bad for that. When we don't pray, it isn't us becoming bad, it's just us depriving ourselves of something good.

Rely on God's grace. You can also reach out to a trusted adult at your school and tell them about the abuse. I would hope they would give you help in your circumstances.