Recently I did quite a strong class of back bends, and I suddenly in the bridge pose I felt very emotional and started crying and had to leave the room. Has anyone else had this sort of thing happen to them?
This is perfectly natural. When you do backbends you open up your heart chakra and this can bring up all sorts of emotions and feelings. Any emotional release in yoga is a positive thing (it sorts out blockages and helps prana / energy to flow).