At least you've got two and a half terms to sort it out. Work hard, especially in Spring and Summer, and speak to a student advisor (not sure if Psychology will have one, but SOCCUL certainly does) about coping, and speak to your personal tutor about the academic side of things.
the most important bit is recognising that you need to buck up your ideas, this is a good place to start.
You may need to do some resit exams in September if you have done as badly as you think, but that's one to discuss with your tutor. I'd also suggest that you don't assume you've done badly, and just concentrate on getting it right from now on.