I don't know a whole lot about psychology graduate prospects, but one thing I do know is that it is very very very very competitive. So many people have psychology degrees, but to have a career in psychology it seems that further education is usually required. Psychology is a good degree in the sense that it can be applied to a wide range of non-psychology jobs, but I can imagine that getting a placement will be tough for anyone who's just graduated.
Still, I would say study what you're most interested in and will do well in. If you want to do Educational Psychology, a psychology degree is a good start but a chemistry degree will obviously not lead you to that career destination. I do understand your concern, because one of main points of having a degree is to aid you in getting a better job afterwards, but I've always felt (perhaps naively) that if you really do well in your degree, get plenty of work experience, etc., you've got a chance of getting a placement.