Your mom is your mom. No matter what happens, she loves you. Remember that.
It's great that you've been thinking about telling your mom. I really, really, really think you should. If you're worried about her telling her friends, mention it and ask her not to.
Don't worry about how she will react, the important thing is that you get this burden off your chest so both of you can take the next step towards you feeling better.
I do hope you tell your mom. Best of luck! ♥