Paul, in Romans 5 tells us that the Holy Spirit is the one who POURS the love of God into our hearts. The actually rendering of the word pour is similar to baptism in that the word means to become fully wet or immersed.
Think about that for a moment--to be "fully wet" or completely "immersed" in the love of God. His love sustains us, encourages us, provides for us, comforts us, and helps us along our way.
The Spirit of God is present to make sure in our lives that we understand the love of God for us. We are children of God and are deeply loved.
If you are struggling with wondering if God loves you--my prayer is that you will no longer struggle but will let the love of God penetrate your heart.