your T will listen to you
as you explain how u came to SI again and that it is not suicidal thought but what you have explained to us
if you are legally an adult then you have the rights to request ur T not to speak to your mother
ur T should explain to you at what stage of risk they may need to report to someone else
examples are in cases where there are risks (serious- as in plans being made) to harm others
or actual suicidal plans being made..

talk to ur T find with their help other more healthier options to SI
for that is part of what they can do