Harinama sankirtana means blending of the loving feelings of many devotees chanting in harmony. When devotees get together and chant Krsna’s holy names full of humility, attachment and love, everyone in that sankirtana party can absorb the various bhavas of one another. This is why sankirtana is so powerful.
Karma produces samskaras in our citta. Go to an astrologer if you want to waste your time sorting out your karma. If you want to transcend your karma and enter the spiritual domain, surrender to guru and practice bhakti.
Grhasthas often ask – should I worship formal deities or some photographs or paintings of Radha-Krishna? What really counts is the bhava. Radha and Krishna can manifest from anywhere if one has bhava. Remember Nrsimhadeva manifested from a stone pillar? Actually, the most important Deities for every devotee are Sri Guru, Srimad Bhagvatam and Sri Nama.
Once you have direct experience of Krishna acting in your life, you will be convinced about Him. But that experience will only come when you surrender.