The Church of our day refuses to claim that someone is in Hell — even if their last act was to kill themselves. Yes, it is always intrinsically evil to aim at the death of an innocent person, and this includes one’s self. But especially in this context, “intrinsically” does not mean “very.” Determining the level of guilt in another person (aside from being something only God can do) is always different from determining whether what they did was morally wrong. Suicide is almost always driven by powerful forces which are beyond the control of the person — especially when it involves mental illness. It is always wrong in the abstract, but the person who does it is often not blameworthy.
This question also invites us to think about how God will judge our lives when it comes to deciding our ultimate destiny. Since the Church considers God to be outside of human time, it is an open question whether we can — at any one time — do something to fundamentally alter our destiny away from union with God in heaven. Because the Church does not speak in clear or absolute terms on these matters, I can only give my personal opinion: I suspect that God sees and evaluates our lives as a whole rather than judging on the basis of one act — especially when that one act is coerced by all kinds of forces beyond one’s control.