Do you think you have been treated poorly because of people's homophobia? You could consider moving to a place that is more gay friendly. If you're just not sure why you are being mistreated, you might consider discussing this specific issue with a therapist.

Some work environments are set up to be 'crud-rolls-downhill/there-can-be-only-one-winner' environments. This is true of where I work and then the powers that be wonder why people aren't nice to each other.

Can you ask for a reassignment if possible when the going on your temporary jobs gets rough?

Is it possible to find a warmer and fuzzier workplace? If the workplace embraces good values, then maybe the employees are held to the same standards? The place you describe sounds like it was basically rewarding that snot nose woman for being mean to you.