According to Osho, the post-discourse drop happens because true merging is a happening, not a doing. In satsang you receive a stronger field; alone, it matures slowly until his presence is felt in your aloneness and in every act. Don't force it - nourish the budding feeling, do everything "for" the beloved, trust, wait, enjoy the 25% - the rest arrives by grace.
You’re not failing; let the feeling grow by itself—keep loving, do your daily things as offerings, and patiently allow the glimpse to become constant.