I have a psych undergrad as well, and before deciding upon OT, I looked at Applied Behavioral Analysis. You can do behavioral therapy, which is more in the psych realm if that's what your goal is.
I also majored in psych. While it's useful for OT because such programs usually have a bunch of psych prereqs, it's certainly not extremely closely related to OT, and certainly doesn't preclude you from doing other things. I majored in psych at a top liberal arts college and quite frankly, most psych majors from my school (really, most people in general) don't work in their major field. That's not the intent when they pick a major - instead, they learn about something in which they have an interest, and develop skills (critical and analytical thinking, writing, etc.) which can be applied in other settings. They're doctors, lawyers, management consultants, financial analysts, etc.. You could do pretty much anything with your psych major, although of course you will need further training for certain fields (such as law, or health careers which require licensing.)
Assuming you mean that you want to stay in something closely-related to psych, and are not just looking for any back-up career, I'd say you could look at social work (MSW) as well as certain areas of business (market research, training, HR, etc..) There are also a number of "counselor" positions at residential treatment centers which do not require an advanced degree or a license.
Of course you can also pursue advanced study of psychology - clinical, experimental, social, personality, neuropsych, etc.. Check the APA website, and post on the psychology forum here.
