Breaking your Purushottama Vrata Fast:

Bhaktivinoda Thakura mentions how the fast breaking in Purusottama month can be celebrated on Krishnapaksh Ashtami, Navami or Chaturdashi tithis. One should worship Radha Krishna in the temple. If this is not possible, then Radha Krishna can be installed in a clay pot. Puspanjali and obeisances should be offered to the Lord. Then one should give donation to the brahmanas and acharya and feed them the highest quality sweet rice with ghee and then break their fast.

Your Well Wisher Always,
Jayapataka Swami

Please note
In India, today (8-6-18) is Navami, tomorrow (9-6-18)is Dasami and the (13-6-18) is Chaturdashi. So your fast can be broken on any of these days.