Typical Tsr. Make fun of a degree that you only have ignorant assumptions of...
The problem isn't necessarily your degree. It's more the fact that you aren't significant to employers. Many employers too make ignorant assumption about Psychology. Work experience is different fields in likely to get you noticed by regular employers. Not just psychology sounding experience.
Like a few have said, to do proper work in Psychology you need to be specifically skilled etc. Placements in Uni can assist this but post graduates are really what companies are looking for. So many people are looking for the same job so obviously the more educate you become the more likely you are to get chosen. It also shows dedication. Anyone can do a psychology degree. It's pretty broad and doesn't necessarily mean you are properly interested in working in the fields of Psychology. Post grad certification can take years. Lots of time and energy as well as money but it makes you a lot more 'legit'
I'd recommend asking people in the jobs you aspire to, for advice or just for them to tell you of their experiences. It is likely to be slightly different due to the people in these jobs being educated awhile back when things were different but there is nothing wrong with a mentor. Network network network.
I think you also need to set clear goals and get out there. Job sites wont cut it. Hit the streets; and yes you may get many rejections. Don't get down though. Many people with degrees can't find jobs. Even law and science graduates. So it's not just a ~Psychology~ thing.