Thank you everyone for all your replies and advice! It's been very helpful!
I managed to speak to my mom a bit.. I didn't bring up the words 'depression' or 'bipolar', but I told her that I have no control over my emotions and for me that's really confusing. My Psychologist suggested she come along to one of my sessions, I'm still nervous about it, but I suppose it might help her understand better..

Thanks again for being so open and honest!