Knowing that we are loved by God does not necessarily dispel fear nor does fear necessarily show a lack of faith. Jesus himself felt anxiety in the Garden. He knew he was loved and certainly believed in his Father. “Perfect love drives out fear” (1 Jn 4) refers to the kind of fear a slave feels and has nothing to do with the anxiety Jesus felt in his agony.
When we are fearful we don't need a feeling of guilt in addition. The spiritual meaning of fear is that we draw closer to Jesus in the Garden of Olives. One of the advantages of being a Christian is that even fear can be a way of drawing closer to God. That doesn't make fear something to be desired, of course, but it does give it meaning.
Whatever its source the best remedy for any fear is the heart of Jesus. He may gently remind us to trust him, as he did Peter walking on the water. Then he will also reach out his hand.
Jesus, you said to your first disciples, “Fear not, it has pleased your Father to give you the kingdom.” If you are with me who or what can be against me? Let me abide in your peace this day.