Dear Mark,
Yes, we are certainly called by God to Love, it is the First of His Commandments. We will struggle because even though Baptism gave us Supernatural Faith, Hope, and Charity (Love), we need to continue asking to receive the increase of those virtues and the Gifts of the Holy Spirit to persevere. As Jesus told His Disciples in John's Gospel: "without Me, you can do nothing" (Jn 15:5)
It seems to me that in focusing on His Love for us, "remaining in Him Who dwells within our hearts" we can hear more clearly "What we are called to do"...especially in prayerfully asking, seeking and knocking on the door, to receive the Gift of Wisdom which perfects Charity, God enables us to grow in holiness.
If we are tempted to discouragement, we need to remember words the Angel spoke to Mary our Mother at the Annunciation in Luke's Gospel: "...with God nothing is impossible" (Lk 1:37)
St. Paul Who wrote the beautiful hymn to Charity (1 Cor 13 ) also wrote in Hebrews these words of encouragement:
Therefore, since we are surrounded by so great a cloud of witnesses, let us rid ourselves of every burden and sin that clings to us and persevere in running the race that lies before us, while keeping our eyes fixed on Jesus, the leader and perfecter of faith. For the sake of the joy that lay before Him He endured the cross, despising its shame, and has taken His seat at the right of the throne of God. (Heb 12:1-2)
Thanks, Mark for pointing us toward Him Who is Love!