Help with some hope and calculations?!

We BD'd on 26th and 30th September due to SO working away; Glow says fertile window from 26th September to 2nd October; Strong positive LH surge 29th and 30th and 1st.

Is there a possibility I could be pregnant? AF due 15/10. I don't "feel" pregnant, but I'm also not getting my usual

AF

*TMI*

diarrhoea and cramping (and this is usually my normal)