How do I say to my online mentor the reason why I have been failing behind on my work?

I learn at home due to mental issues. I'm not sure my online mentor (i've got a computer where I log on and do the work and send it to my mentor) is aware of everything. And recently my mental health problems have been getting way way outta control which is making me fail on my work, haven't submitted any work, haven't been in contact etc. I haven't spoken to any of my family relatives about it but they are becoming more aware of it now. I need to tell her but I'm not sure how to say it, it's too embarrassing. Any ideas. Serious Answers please.