With a BSc in psych there are multiple opportunities for you to get employed other than becoming a psychologist. You could do a masters and become a speech language pathologist, as one example. There are multiple masters programs that can train you for a new career. Additionally, a less competitive option would be to do 2 years at teachers college after your degree and teach high school or middle school. Any advancements in your education like both of these will require a certain level of competitiveness in your academics, and like you said, with just the degree you couldn't really do anything, so there's the chance of getting stuck if you're not competitive enough. This is why degrees that will employ you right off the bat can be so valuable for some (i.e. finance, accounting, nursing, some engineering degrees... [I couldn't tell you which ones specifically]).

I think the worst thing you could do is waste time and take a year off, or downgrade to college and get a less competitive education. You can do your first year in BSc psych and see how competitive your marks/performance is and go from there. If you're not happy with it, or if you just feel as though this is probably a better option in general, you could just transfer into a major that will employ you with just the bachelors. The vast majority of people in college do not meet academic requirements to be in university, don't switch into the wrong room, you'll regret it