Poor you. I would imagine there were a few woman on the bus who have been in your shoes and I am surprised they weren't the first to offer you a seat. Did they make loud comments about the young man? Didn't offer a seat though, but did a lot of tutting. Shame on them too.
I am of the opinion that most people on any form of shared transport have no manners and have flown Ryanair before. There is no hope.