Sex and periods.

A day before my period me and my SO had unprotected sex. He came In me on the 19th and then the 21st, again we had unprotected sex, which later on that day I started my period. It lasts for 5 days, so I'm assuming it's like 26-28 cycle length. I stopped the 25th, we than had unprotected sex the 27th and 28th. What are my chances of getting pregnant? Could I have got pregnant before I started? It says my fertile window is the 30-5th or 6th. I think day 3 being my peak day. Any thoughts ?